1756 - Operations on Lake Ontario

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Hierarchical Path: Seven Years War (Main Page) >> Campaigns >> 1756 - Operations on Lake Ontario

The campaign lasted from May to August 1756


Preparations for the campaign

For the 1756 campaign in North America, the British planned four offensives:

  • an attack against Fort Carillon (present-day Ticonderoga) and Fort Saint-Frédéric (present-day Crown Point) in the Lake Champlain area;
  • an expedition on Lake Ontario with strong naval and land forces to seize the French forts upon it: Niagara, Frontenac (aka Cataraqui, present-day Kingston), and Toronto;
  • an attack on Fort Duquesne (present-day Pittsburgh) in the Ohio Valley;
  • a diversionary attack down the Chaudière River upon the settlements about Québec.

A British garrison of about 1,600 men, mainly regulars, under Lieutenant-Colonel Mercer had wintered at Oswego on Lake Ontario and had suffered heavy losses from scurvy and inadequate rations.

At the beginning of 1756, General Shirley was still commander-in-chief. He chose to personally lead the amphibious expedition against the French forts on Lake Ontario. His land forces consisted of the remains of:

Shirley's first concern was to bring his regiments to their full complement. Through recruitment he brought his force to some 4,400 men.

Detailed map of the campaign - Copyright: Kronoskaf

Early in 1756, Captain Housman Broadley was sent to Oswego to command the small British flotilla being built to control Lake Ontario.

On February 26, 40 carpenters arrived at Oswego to build new vessels, but they remain idle because there were no guards to protect them.

In March, the Earl of Loudon was appointed commander-in-chief of the British forces in North America.

In April, Shirley learned that he would be superseded in the command. Colonel Daniel Webb would be sent to America, followed by General James Abercromby and finally by the Earl of Loudon, the eventual commander-in-chief. Shirley was to resign his command to Webb, Webb to Abercromby, and Abercromby to Loudon. Meanwhile, Shirley was still responsible for the preparation of the campaign.

On paper, the defence of Oswego was based on the idea of securing Lake Ontario with a naval force stronger than the ships the French could assemble at Frontenac (to the northeast), or Niagara (to the west). Shipbuilding was a chief focus and competed with work to improve the fortifications. Fitting the ships was proving slow and time-consuming. Crews and rigging were lacking.

At the beginning of May, Vaudreuil, the governor of Canada, sent Coulon de Villiers with a force of 660 men (100 French regulars and 400 Canadian militia, 100 Resident Indians and 60 Allied Menominees, aka Folles Avoines Indians), to harass Oswego and cut its communications with Albany. He established a permanent camp at Niaouré Bay (present-day Sackett's Harbor).

On May 7, Shirley arrived at Albany from New York to continue his preparations. He established his headquarters in Albany and first rebuilt the Fort at the Great Carrying Place (near present-day Rome, New York) that had been destroyed by the French just a month before (March 1756).

On May 11, Indians killed 10 British carpenters and captured 3 others near Oswego.

On May 16, Patrick Mackellar, an army engineer, arrived at Oswego with Lieutenant-Colonel Bradstreet and a convoy of bateaux with provisions and naval stores.

On May 17, Mackellar reported to Colonel Mercer the defects that he had identified while inspecting the fortifications of Fort Oswego and Fort George and asked for men to repair these forts. A council of war was immediately held where it was decided to give priority to the construction of ships. The same day, a party of Indians attacked the detachment covering the bateaux, killing Lieutenant Blair, 1 Mohawk and 1 soldier and wounding another soldier.

On May 18, the II./Béarn Infanterie left its winter-quarters and assembled in Montréal.

A French expedition departs for Lake Ontario

On May 19, the expedition under the command of Coulon de Villiers left Montréal for Niaouré Bay.

On May 24

  • French
    • The first division of II./Béarn Infanterie (7 coys) embarked at Lachine aboard 21 boats.
    • At 11:00 p.m., a party of Indians attacked boatmen who were encamped near Fort Oswego, killing 4 men, wounding 2 men and taking 2 prisoners.

On May 25

  • French
    • The second division of II./Béarn Infanterie (6 coys including the grenadier coy) embarked at Lachine aboard 21 boats.
  • British
    • In the afternoon, Colonel Peter Schuyler and Major Kineer arrived at Oswego with 170 men of the New Jersey Provincials, bringing a convoy of bateaux with naval stores. A drove of oxen also arrived.

On May 28 in the morning, Captain Richmond of the New York Independent Companies marched off from Oswego for German Flats with his company.

On May 29, Bougainville arrived at Montréal after travelling from Québec in one of the King's canoe.

In June, Webb arrived in New England. Meanwhile, Mackellar estimated that the works at Oswego were incapable of defense. The Shirley's 50th Regiment of Foot had lost half of its effectives while wintering at Fort Oswego. The Pepperrell's 51st Regiment of Foot quartered at Fort Ontario on the other side of the river had suffered less. During the same month, Shirley posted detachments in the newly built forts on the Mohawk River and at the Great Carrying Place. He also took into pay 2,000 boatmen, including many whale-men from the eastern coasts of New England, divided them into companies of 50, armed each with a gun and a hatchet and placed them under the command of Lieutenant-Colonel John Bradstreet (essentially this was a provincial rank; Captain Bradstreet was not promoted to lieutenant-colonel in the British Army until late 1757).

On June 4 and 5, II./Béarn Infanterie arrived at Fort Frontenac.

On June 9, II./Guyenne Infanterie arrived at Fort Frontenac.

On June 14, leaving 3 coys and the piquets at Fort Frontenac, II./Béarn Infanterie embarked for Fort Niagara aboard:

  • the Marquise de Vaudreuil (8 x 8 pdrs, 4 x 4-pdrs, six swivels, and a crew of 30 men) transporting 3 coys
  • the Thurault (aka Huron) (8 x 6-pdrs, 4 x 4-pdrs, a crew of 80 men and 40 marines) transporting 3 coys
  • the Louise (8 x 3-pdrs) transporting 2 coys
  • the Victor (4) transporting 2 coys

On June 4, a French schooner was seen passing “12 Mile Point” and a British schooner was sent in the evening to discover her with no result.

On June 5, two vessels under Captains Bradley and La Forey, and a small schooner went out from Oswego.

On June 15, bad weather forced the four French vessels to disembark the II./Béarn Infanterie on the Coui Islands (probably part of the Thousand Islands on Lake Ontario, west of Fort Frontenac).

On June 16 at 4:00 a.m., a party of some 150 Indians attacked the detachment (1 sergeant, 1 corporal, 12 men) guarding the bateaux near Oswego, only 2 men managed to escape, the rest were killed or taken.

On June 17, five whale boats scouted eastwards from Oswego. In the evening, they returned, reporting that they had been fired upon from the shore by a large party of Indians (approx. 1,000 men) some 32 km east of the forts.

On June 18

  • French
    • Troops re-embarked and the four French vessels sailed from the Coui Islands.
  • British
    • A convoy of bateaux and whale boats arrived at Oswego, from Albany.

On June 20, Major-General Abercromby arrived at New York with the 35th Otway's Regiment of Foot and the I./42nd Highlanders.

On June 21

  • French
    • The four French vessels reached Toronto.
    • Bourlamaque left Montréal for Fort Frontenac.
  • British
    • At Oswego, Mackellar started to work at a defensive work for the advanced guard.

On June 22, the four French vessels finally reached Fort Niagara where the II./Béarn Infanterie encamped in the defensive works.

On June 23, the British sent out two large vessels, two schooners and eight whale boats from Oswego to cruise and scout on Lake Ontario.

On June 24 in the afternoon, a considerable body of Indians (approx. 150 men) fired upon the little British schooner and seven whale boats from one of the islands off Portland Point and captured one whale boat.

On June 25, the British schooners and the whale boats returned to Oswego.

On June 26

  • French
    • The 4 coys of II./Guyenne Infanterie who had wintered at Fort Niagara re-embarked to join the rest of the battalion at Fort Frontenac.
  • British
    • In the evening, Captain McPhun went out of Oswego in the little schooner.

On June 27

  • French
    • The chief engineer Descombes was ordered to sail from Fort Frontenac, join de Villiers' detachment and reconnoitre Fort Oswego.
    • Two French “barks” chased the sloop Ontario (4 x 4-pdrs, 1 x 3-pdr, 10 x swivels and a crew of 45) and the great schooner (6 x swivels, Captain Jasper Farmer and a crew of 15) back towards Oswego, and managed to capture the great schooner.
    • Montcalm and Lévis left Montréal for Fort Carillon on Lake Champlain

On June 28

  • French
    • A French vessel chased Captain McPhun into the harbour of Oswego.
  • British
    • Bradstreet arrived at Three Rivers with a large convoys of bateaux and asked Colonel Mercer for a detachment of 100 men to cover the building of a fort at the Great Falls. Mercer held a council of war where it was decided to reject Bradstreet’s request because all hands were needed at Oswego.

On June 30, Mackellar completed the defensive work round the advanced guard at Oswego. His men then started to build fascines.

The delays imposed on Shirley's expedition had given the French time to secure all their posts on Lake Ontario. Before the end of June this was in good measure done. The II./Béarn Infanterie lay encamped before the now strong Fort Niagara and the II./Guyenne Infanterie and the II./La Sarre Infanterie, with a body of Canadians, guarded Fort Frontenac against attack.

At the end of June, Abercromby and Webb arrived at Albany with a reinforcement of some 900 men consisting of the 35th Foot and the I./42nd Highlanders. Shirley then resigned his command and returned to New York to wait for the arrival of Lord Loudon and inform him of the state of affairs.

At the beginning of July, Sir William Johnson persuaded the Iroquois Confederacy to ally with Great Britain in its fight against the French.

On July 1, despite the French force threatening the communications between Albany and Fort Oswego, Bradstreet safely conducted a convoy of provisions and military stores to the garrison of Oswego. The delivered stores included six 6-pdrs, ten 4-pdrs, fourteen swivels, and ship rigging. These were ship guns. However, there was a clear need for both additional guns and rigging. Captains Moore and Paget accompanied the convoy with a party of 150 men.

On July 2, Mackellar began a Fascine Battery upon the north wing of the hornwork towards Lake Ontario to secure that wing and to defend the entrance of the harbour.

Engagement near Oswego

On July 3 in the morning, Bradstreet set out on his return to Shenectady with the empty boats. He divided his force into three divisions. The first of these, consisting of some 100 boats and 300 men, with Bradstreet at their head, were about 14 km from Oswego, when, at 3:00 p.m., they received a heavy volley from the forest on the east bank. It was fired by a part of Villiers' command, consisting of about 700 men (180 regulars, 400 Canadiens and 100 Indians by British account, only 400 men according to Bougainville). A considerable number of the boatmen were killed or disabled and the others made for the shelter of the western shore. Some prisoners were taken in the confusion.

The French then tried to cross under cover of an island just above. Bradstreet saw the movement, and landed on the island with six or eight followers, among whom was young Captain Schuyler (afterwards General Schuyler of the Revolution). Their fire kept the French in check till others joined them, to the number of about 20. They repulsed the French two more times.

The French gave over the attempt and made for another ford at some distance above. Bradstreet saw their intention and, collecting 250 men, was about to advance up the west bank to oppose them when Dr. Kirkland, a surgeon, came to tell him that the second division of boats had come up, and that the men had landed. Bradstreet ordered them to stay where they were and defend the lower crossing.

Bradstreet then hastened forward; but when he reached the upper ford, the French had passed the river and were ensconced in a pine-swamp near the shore. Bradstreet attacked them and both parties fired at each other from behind trees for an hour, with little effect. Bradstreet at length encouraged his men to make a rush at the French, who were put to flight and driven into the river, where many were shot or drowned as they tried to cross. In this affair, the French lost 1 colony officer, 6 Canadiens and colony soldiers and 1 Indian.

Another party of the French had meanwhile passed by a ford still higher up to support their comrades but the fight was over before they reached the spot, and they in their turn were set upon and driven back across the stream. Half an hour later, Captain Patten arrived from Onondaga with the grenadiers of Shirley's 50th Regiment of Foot and, late in the evening, 150 men came from Oswego under Captain Paget to reinforce the victors. In the morning Bradstreet prepared to follow the French to their camp, 19 km distant but was prevented by a heavy rain that lasted all day.

The same day (July 3) at 10:00 a.m., the British launched a 16-gun brig and a 12-gun sloop at Oswego. No men were allocated to the building of defensive works.

On July 4 around 2:00 p.m., Captain Moore was sent out with 200 men after a report came in that the French were encamped about 12 km on the east side of the Oswego River

On Monday July 5

  • British
    • In the afternoon, Captain Moore’s detachment returned to Oswego along with Captain Patten and 112 men from Onondaga who had joined them during their reconnaissance.
    • After a council of war, Mercer decided to employ no more workmen upon the fortifications for want of money.
    • Bradstreet and his men reached Albany, bringing two prisoners, 80 French muskets, and many knapsacks picked up in the woods. He had lost between 60 and 70 killed, wounded, and taken. The French prisoners declared that the French meant to attack Oswego.

On July 9, two scouting parties were sent out from Oswego but they did not discover any enemy.

Vaudreuil had conceived a plan to secretly send an expedition against Oswego to alleviate the pressure of the British forces against Fort Carillon.

On July 10, Vaudreuil recalled Montcalm and Bougainville, his aide-de-camp, from Carillon with some troops.

On July 11 at noon, Marin arrived at Montréal with 40 Menominees from beyond Lake Michigan.

On July 12, a band of 10 Ojibwes arrived at Montréal.

On July 15

  • French
    • Rigaud left Montréal with Léry, Courtemanche and Ligneris to take command of the Indians and Canadiens assembled at the camp of M. de Villiers at Niaouré Bay.
    • The Menominees accepted to join the expedition against Oswego.

On July 17, a scouting party was sent out from Oswego but it did not discover any enemy.

On July 18

  • French
    • Marin left Montréal with the Menominees, on their way to Lake Ontario.
  • British
    • Ensign Grant was sent out with some whale boats to reconnoitre eastwards.

French expedition against Fort Oswego (Fort Chouaguen)

On July 19

  • French
    • Montcalm arrived in Montréal where he was reinforced with troops from Québec and Indians from the far west.
    • M. Mercier left Montréal for Fort Frontenac to prepare the artillery for the expedition against Oswego.

On July 21, Montcalm left Montréal for Fort Frontenac at the head of a strong expeditionary force to attack Oswego. The works at Oswego consisted of three forts: Fort Oswego proper, Fort Ontario located on the opposite bank of the river and Fort Rascal an unfinished work. However, by that time, Shirley had already replenished the ranks of the [[50th Foot] and 51st Foot and was in a better position to resist an attack.

On July 22 in the morning, Ensign Grant returned from his reconnaissance and informed Lieutenant-Colonel Mercer that the French had established a camp at Niaouré Bay. In the afternoon, a 18-gun snow was launched at Oswego.

On July 23

  • French
    • The II./Béarn Infanterie, leaving a small garrison at Fort Niagara, embarked aboard four vessels to join the small army assembling at Fort Frontenac.
  • British
    • At Oswego, the officers managed to convince their soldiers to resume work on fortifications even if they had not been paid. The soldiers started digging a ditch round Fort Ontario and improving its fortifications; at Fort George, they made platform, footbanks, repaired the parapet and dug the ditch.
    • The little schooner and some whale boats were sent to reconnoitre eastwards but did not make any discovery.
    • Loudon finally arrived at New York. He then sailed up the Hudson.

On July 25, the little schooner was sent eastwards from Oswego but did not find any enemy.

On July 26, the little schooner and some whale boats were to reconnoitre eastwards and then westwards from Oswego but did not make any significant discovery.

On July 27, Rigaud reached Niaouré Bay with a party of 700 Canadians to reinforce Villiers, Rigaud then took command of their united forces. From this location, the engineer Descombles reconnoitred the forts at Oswego and reported about the certain success of the expedition.

On July 29

  • French
  • British
    • The Earl of Loudon arrived at his headquarters at Albany. He then assumed command of the army. Upon his arrival, Loudon decided to abandon the attempt against Niagara and Frontenac, resolving instead to turn his whole force against Fort Carillon. However, a few days later, Bradstreet informed Loudon that the French were preparing to attack Oswego with about 1,200 men.

On July 30

  • French
    • 8 sailors of the Léopard (62) arrived at Fort Frontenac from Québec to serve as cannoneers. The French had gathered 137 bateaux (14 more arrived during the day) and 6 canoes (excluding those of the 165 coureur des bois).
    • The four vessels transporting II./Béarn Infanterie set off once more from Fort Niagara.
  • British
    • The new 16-gun brig, the new 12-gun sloop and the old 6-gun vessel went out of Oswego with a command of men on board.

On July 31

  • French
    • At 3:00 p.m., II./Béarn Infanterie disembarked at Fort Frontenac.
    • 14 additional bateaux arrived at Fort Frontenac.
  • British
    • In the morning, the small British flotilla came back to Oswego. The brig had sprung one of her masts and the old vessel her boom.

At the time of Montcalm's attack, the British "navy" on Lake Ontario consisted of

  • the London (14), a new brig with 6 x 6-pdrs, 8 x 4-pdrs, 14 swivels
  • the Vigilant (6), a new sloop with 4 x 4-pdrs, 2 x 3-pdrs, 12 swivels
  • the Ontario (6), a one-year-old sloop with 6 x 4-pdrs, 2 howitzers, 12 swivels
  • the Oswego, a sloop who had been stripped of her guns and crew to fit the London (14)
  • a one-year-old schooner of twelve swivels
  • a “snow” (probably named Halifax) designed for 18 X 6-pdrs, who had been launched on July 22. Fitting of the ship continued, but the rigging was minimal and there were no guns.
  • a small schooner was in the stocks. Smaller, low-draft vessels were needed to scout the shorelines, rivers, and embayments. This is the only ship that was burned by the French. All the other vessels were taken to Frontenac.
  • some 200 bateaux

During the night of August 4 to 5, after waiting a few days for the arrival of the II./Béarn Infanterie from Fort Niagara, Montcalm left Fort Frontenac at the head of a force of more than 3,000 men consisting of:

  • Regulars (approx. 1,100 men)
  • Troupes Franches de la Marine (137 men)
  • Milices Canadiennes (approx. 1,500 men)
  • Resident Indians (234 men)
  • Allied Indians (36 men)
  • Artillery (33 pieces)
    • 4 x light 12-pdr brass guns (captured on the Monongahela in 1755)
    • 2 x 6-pdr brass guns (captured on the Monongahela in 1755)
    • 2 x 2-pdr brass guns
    • 4 x 12-pdr iron guns
    • 6 x 8-pdr iron guns
    • 4 x 6-pdr iron guns
    • 2 x 8-in brass howitzers (captured on the Monongahela in 1755)
    • 1 x 6-in iron mortar
    • 8 x iron grenade mortars

At 9:00 p.m., Montcalm and Bougainville reached the Isle aux Chevreuils (present-day Wolf Island) at midnight with the first division. Montcalm planned to move his flotilla (more than 200 bateaux) primarily at night, coasting the shore.

On August 5

  • British
    • The new brig and one of the 6-gun vessels went out of Oswego upon a cruise.
    • An Indian scout reported that he had seen 28 bateaux the previous day coming along the lake.

During the night of August 5 to 6, after spending the previous day hidden on Isle aux Chevreuils, Montcalm embarked again with the first division.

On August 6

  • French
    • At 7:00 a.m., Montcalm personally joined Rigaud at Niaouré Bay.
  • British
    • Lieutenant-Colonel Mercer, commanding at Oswego, was informed that there was a large French encampment about 20 km from his fort.

On August 7

  • French
    • At 9:00 a.m., the first division of Montcalm’s Army reached Rigaud’s camp at Niaouré Bay.
    • At 10:00 a.m., an Indian war party set out from Niaouré Bay.
    • At 4:00 p.m., a detachment of 20 Indians left for the Oswego River to try to intercept British couriers.
    • The second division was still on its way, with provisions, hospital train, and 80 artillery boats.
  • British
    • The British brigantine that was cruising Lake Ontario with two sloops (including the HMS Ontario) returned to Oswego. While entering the harbour, the brigantine was driven by a gale of wind upon rocky ground. She was stranded for 18 hours.
    • In the morning, the small schooner went out to reconnoitre but failed to detect the advance of the French.

On August 8

  • French
    • The vanguard (400 Canadiens and all the Indians) left the camp under Rigaud’s command and reached Anse-aux-Cabanes, some 16 km from Oswego.
    • The second division and the heavy artillery joined the first division at Niaouré Bay.

On August 9

  • French
    • At 2:00 a.m., Rigaud’s vanguard reached Anse-aux-Cabanes, about 12 km from Oswego, after marching under the cover of the dense forest.
    • At 5:00 a.m., Montcalm followed with the first division and, coasting the shore in bateaux, reached the Rivière aux Sables, som 20 km from Niaouré Bay.
  • British
    • The London (14) was not seaworthy. The British "heaved her down" to examine the damage to the keel; some 3-inches of the keel had been lost. Over the next several days, a false keel would be placed and much necessary work was done to better chalk the hull in an effort to keep the magazines dry. The quality of the ship building had suffered because of the need to use green, non-seasoned wood.

On August 10

  • French
    • At 10:00 a.m., Rigaud’s vanguard marched through the woods and took position at Petite Anse to cover the landing of the first division.
    • Indian scouts advanced on Oswego. Outside of Fort Ontario, a soldier of the 51st Foot was scalped.
    • The first division landed at midnight at Anse-aux-Cabanes. Four cannon were planted in battery upon the strand, and the men bivouacked by their boats.

Siege and capture of Oswego

There is one source of considerable confusion. The British engineer Patrick Mackellar leaves a detailed account of the events from May 16 through August 14, plus a detailed map. However, in most French accounts, Mackellar's Fort George is referenced as Fort Oswego, and Mackellar's Fort Oswego is referenced as Fort George - the names are switched. This article follows Mackellar's designations.

In the morning of August 11, Montcalm advanced within 2 km of Oswego. The British small schooner finally discovered the French forces. The Ontario (12) and Vigilant (6) soon came to cannonade them but their light guns were no match for the heavy 12 pdr guns of the French positioned on the shoreline, and they were forced to withdraw after a fight of more than an hour. The Ontario was holed by three 12-pound shots. Descombles, the engineer, was mistakenly shot by an Indian during a reconnaissance. M. Desendroin then assumed command of the engineers assisted by M. de Pouchot, captain of Béarn Infanterie, and the attack was pushed vigorously. The Canadians and Indians fired all day on the forts under cover of the trees.

During the night of August 11 to 12, the first parallel was marked out at 160 meters from the rampart. Stumps were grubbed up, fallen trunks shoved aside, and a trench dug, sheltered by fascines, gabions, and a strong abattis.

Fort Ontario, counted as the best of the three forts at Oswego, stood on a high plateau at the east or right bank of the Oswego River where it entered the lake. It was in the shape of a star, and was formed of trunks of trees set upright in the ground, hewn flat on two sides, and closely fitted together. This type of palisade was an excellent defence against musketry or swivel guns, but worthless against cannon. Fort Ontario was garrisoned by 370 men who were the remnant of the 51st Pepperrell's Regiment of Foot, joined by raw recruits lately sent up to fill the places of the sick and dead. They had eight small cannon and a mortar.

On August 12

  • French
    • Montcalm requisitioned 100 men per battalion (50 workers and the grenadier coy) to work at the trenches.
    • Montcalm's second division came up with 22 more guns.
  • British
    • The Ontario (12) and the Vigilant (6) patrolled the shoreline and guarded the approaches to the harbour, but only briefly engaged the French shore batteries. The British rushed to finish repairs to the much larger London (Brig, 14). These repairs were completed late in the day. The British planned to send out all three vessels the next morning.
    • Ignorant of Montcalm's offensive but fearing a French attack on Oswego, Loudon sent Webb forward from Albany with the 44th Regiment of Foot and some of Bradstreet's boatmen to reinforce the forts.
Map of the Siege of Oswego
Courtesy: Dinos Antoniadis
Key to the map:
A Block House
B Traders Houses
C Hospital and Bolting House
D Bake House
E Ditch with Fort Oswego constructed on August 13
FF Entrenchment at Fort Oswego laid out in the Morning of August 14
G Batteries of Pork Casks against Fort George, constructed the Evening of August 13
H Carpenters Houses
I Smith’s Shop
K Parallel begun by the French in the evening of August 11
L Batteries against Fort Ontario
M Approaches made on August 13 at night against Fort George
NN Battery en Barbette against Fort George, constructed in the evening of August 13
P Dock
Elevations above lake level
Fort George 20 ft
Fort Oswego 70 ft
Fort Ontario 50 ft

Just east of the mouth of the Oswego River, Fort Ontario was positioned on a rise to secure the harbour. However, the ground to the north and east was even higher in elevation. On Friday August 13, the French were establishing their works and batteries on this higher ground. Once completed, these French batteries would be exceedingly close, less than 100 meters from the fort walls — easily within the envelope of a breaching battery. The cannon in Fort Ontario could not elevate enough to fire on these positions and the arching British mortar fire proved ineffective. Throughout the day, (the garrison of Fort Ontario kept up a brisk fire from 6:00 a.m. till towards night then it ceased. Not a single gun had yet opened on them from the trenches but it was certain that the fortification could not withstand the French artillery fire. Consequently, Lieutenant-Colonel Mercer, commandant at Fort Oswego, signaled to the garrison from across the river to abandon their position and to join him on the other side. Boats were sent to bring them off; and they passed over unmolested, after spiking their 8 cannon, 4 mortars and spoiling their ammunition. The French immediately took possession of Fort Ontario. Throughout the day, the British ships had been trapped in the harbour by a combination of slack winds and a sediment bar blocking the exit.

The principal work, called Old Oswego, or Fort Pepperrell, stood at the mouth of the river on the west side, nearly opposite Fort Ontario, about 450 meters distant from it. The trading-house, which formed the centre of the place, was built of rough stone laid in clay and the wall that enclosed it was of the same materials. Towards the west and south it had been protected by an outer line of earthworks, mounted with guns and forming an entrenched camp. The side of the fort towards Fort Ontario was left wholly exposed. On a hill, 400 meters beyond Old Oswego, stood the unfinished stockade called New Oswego, or by reason of its worthlessness, Fort Rascal. It had served as a cattle pen before the French appeared, but was now occupied by 150 New Jersey Provincials. The 50th Shirley's Regiment of Foot, joined by the garrison of Fort Ontario and a number of sailors, boatmen, and labourers, held Old Oswego with its outwork.

During the night of August 13 to 14, Montcalm lost no time. As soon as darkness set in he began a battery at the brink of the height on which stood the captured Fort Ontario. His whole force toiled all night, digging, setting gabions, and dragging up guns. Before daybreak 20 heavy artillery pieces had been brought to the spot, and nine were already in position.

On August 14, the battery, served by 60 gunners and 50 soldiers, opened fire at 8:00 a.m. Grape and round shot swept the entrenchment and crashed through walls of Old Oswego. The British had to move their guns from the west to the east side of their fortification, making a shelter of pork-barrels, three high and three deep, and planting their guns behind them. Ship crews were moved ashore to aid in the defence.

Early in the morning of August 14, Montcalm ordered Rigaud to cross to the west bank of the river with the Canadians and Indians. There was a ford 3 km above the forts where they passed over unopposed. Around 9:00 a.m., they showed themselves at the edge of the woods near Old Oswego, further demoralising an already disheartened garrison. Lieutenant-Colonel Mercer had just been cut in two by a cannon-shot while directing the gunners. After a council of the officers, Lieutenant-Colonel Littlehales, now in charge, raised the white flag. Bougainville went to propose terms of capitulation which were soon concluded. The British surrendered prisoners of war to the number of about 1,400, exclusive of civilians. At 1:00 p.m., the French took possession of the fort, which was plundered by the Canadians and Indians.

Inventories prepared by Captain Le Mercier
François Le Mercier was Montcalm's artillery officer. He was not a French Army officer, but the commander of a company of the Canonniers-Bombardiers de la Marine – troops who serviced the artillery in France's overseas colonies, administered by the Navy. Le Mercier had arrived in Canada in 1740, reaching the rank of captain in 1753. Among his duties was preparing ordnance inventories. Some dozen of these inventories are at the Library Archives Canada. In Fall 1756, Le Mercier prepared the inventory for Fort Frontenac on the north shore of Lake Ontario (Le Mercier Inventory, October 20, 1756, Library Archives Canada, ID # 3072938, on-line). This is where much of the captured ordnance from Oswego was first taken. This inventory confirms that many of the captured shell pieces were indeed iron, not brass, including an iron 8-inch howitzer which had to be American cast. Canadian cast 6-inch iron mortars and smaller grenade mortars also appear in this inventory. These were cast at the Forges du Saint-Maurice, at Trois-Rivières in Canada about 1748. However, the Le Mercier Inventory of Carillon (September 26, 1757, ID # 3073056, on-line) confirms that the coehorn mortars were indeed brass and British cast.

During this siege, the British lost 40 killed while the French lost 1 engineer and 13 men killed and 8 wounded. In the forts and vessels were found 123 pieces of artillery, most of them swivels and other light guns, with a large quantity of powder, shot, and shell. More precisely:

  • 1 x 18-pdr brass gun
  • 2 x heavy 12-pdr brass guns
  • 4 x medium 12-pdr brass guns
  • 1 x 8-in iron howitzer (conflicting French inventories - brass or iron piece; American cast)
  • 1 x 10-in brass mortar
  • 1 x 8-in iron mortar (burst during siege? conflicting inventories - brass or iron)
  • 5 x royal 5½-in iron mortars (American cast?)
  • 5 x 4⅖-in iron howitzers – Shirley's squivel hoyetts (American cast)
  • about 11 x 4⅖-in coehorn brass mortars
  • 23,000 weight of gunpowder
  • 2,950 round shot
  • 150 10-inch shells
  • 300 8-inch shells
  • 48 additional iron cannon
  • 47 swivel guns

Although the British planned to burn their ships prior to any surrender, there was poor communication; the surrender was agreed to before any of the ships could be set afire.

On August 15

  • French
    • Montcalm's Army rested. He incorporated the captured brass artillery pieces in his own artillery.
    • Two armed French vessels entered the port of Oswego.
    • 228 British prisoners left Oswego for Montréal aboard 20 bateaux, escorted by 30 soldiers.

On August 16, 150 French soldiers were charged to burn the forts and any unwanted ships or bateaux, to destroy such provisions and stores as they could not carry away and to make the place a desert. Some of the captured ships, including the London (14), were used to haul provisions and stores to Fort Frontenac. These were then subsequently added to the French Feet.

On August 17

  • French
    • 32 British prisoners left for Montréal.
    • The Menominees left to return home.
    • In the evening, three captured British vessels left Oswego, transporting the captured artillery.
  • British
    • Webb had reached German Flats when he received news that Oswego was in the hands of the French. He immediately ordered the commanding officer at the Great Carrying Place to obstruct the passage of the Wood Creek. When Webb arrived at the Great Carrying Place the entire British force there amounted to more than 2,500 men, including 1,500 regulars, seamen and boatmen. Furthermore Johnson was marching thither with the Albany militia. Webb encamped at the Great Carrying Place, fortified his camp and deployed 28 guns to protect it.

On August 18, what remained of the fortifications was burned to the ground. The French also burnt a vessel still on the stocks.

When he received an erroneous report that 6,000 French were advancing upon New York, Webb, with shameful precipitation, burned the fort at the Great Carrying Place and retreated down the Mohawk River to German Flats and then to Albany.

On August 19, the rest of the British prisoners embarked aboard boats and set off for Fort Frontenac and Montréal.

On August 20 at noon, Chabert de Joncaire arrived at Oswego with 50 Iroquois coming from Niagara. All barges and bateaux that could not be taken away were burned.

On August 21 at 7:00 a.m., Montcalm’s Army set off from Oswego, on its way to Montréal. It encamped at Rivière aux Sables for the night.

Loudon ordered Winslow to abandon his campaign against Fort Carillon but to stay where he was and hold the French in check.

On August 22 at 9:00 a.m., Montcalm’s flotilla set off from Rivière aux Sables in bad weather. The lake was very rough. The army encamped at Niaouré Bay.

On August 23

  • French
    • II./Béarn set off from Niaouré Bay with 260 prisoners to return to Lachine, leaving a detachment destined for Fort Frontenac.
    • At noon, the rest of the flotilla left but it was forced by strong winds to go ashore and to bivouac at Isle aux Chevreuil.

On August 24, II./Béarn and Montcalm’s flotilla reached Fort La Présentation.

On August 26, Montcalm personally arrived at Montréal. At 7:00 p.m., II./Béarn arrived at Lachine and later went to its quarters in La Prairie.

Canadian militia had also been sent back to Canada for the harvest.

On August 27, II./Guyenne reached Lachine.

At the end of August, all British prisoners were transferred from Montréal to Québec. where they were put on board a merchant ship which set sail directly for Portsmouth in Great Britain, where they were exchanged for the same number of French prisoners.

In September, most of the French regulars took the road to Fort Carillon to reinforce Lévis in these quarters. The II./La Sarre Infanterie had been left behind at Saint-Jean on the Richelieu River. Some detachments were also sent to Niagara and Frontenac. Supplies captured at Oswego were sent to Niagara, Frontenac and Belle-Rivière (present-day Ohio River).

France had now taken undisputed command of Lake Ontario, and her communications with the West were safe.


This article incorporates texts from the following books, which are now in the public domain:

  • Anonymous: A Complete History of the Present War, from its Commencement in 1756, to the End of the Campaign, 1760, London, 1761
  • Bougainville, Louis Antoine de: Adventure in the Wilderness - The American Journal of Louis Antoide de Bougainville 1756-1760, Norman: University of Oklahoma Press translated by Edward P. Hamilton, pp. 3-30
  • Fortescue, J. W.: A History of the British Army Vol. II, MacMillan, London, 1899, p. 297.
  • Lévis, chevalier de: Journal des campagnes du chevalier de Lévis en Canada de 1756 à 1760, Montréal, Beauchemin, 1889, pp. 63-66
  • Malartic, Comte de Maurès de: Journal des Campagnes au Canada de 1755 à 1760, Dijon: Damidot, 1890, pp. 58-79
  • Parkman, Francis: Montcalm and Wolfe, Collier Books, New York, 1884, pp. 223-241

Other sources

Castex, Jean-Claude: Dictionnaire des batailles terrestres franco-anglaises de la Guerre de Sept Ans, Presse de l'université Laval, Québec: 2006, pp. 134-138.

Dechêne, Louise: Le Peuple, l’État et la Guerre au Canada sous le Régime français, Éditions du Boréal, 2008, pp. 500-503.

Grant, W. L. 1914. The Capture of Oswego in 1756. Proceeding of the New York State Historical Association, Vol. 13, Pages 339-367.

O'Callaghan, E. B. 1858. Documents Relative to the Colonial History of the State of New York: Procured in Holland, England and France. Vol. X, Weed Parsons and Company, Printers, Albany. Online, pp. 482, 485.

Pargellis, Stanley 1936. Military Affairs in North America, 1748-1765. "MANA". Selected Documents from the Cumberland Papers in Windsor Castle. American Historical Association, 1936. Reprinted: Archon Books, 1969. pp. 187-219.


Kenneth P. Dunne for the detailed breakdown of Montcalm's artillery and of the British artillery pieces captures at Oswego; and for information on the fleets operating on Lake Ontario