Stoa of the Herms
From Project Athinai
As per historical records, the Stoa of the Herms was located near the Agora. It already existed in 425 BC. However, the current archaelogical excavations have not yet found its location. Some authors think that it was probably located to the west of the Stoa Poikile.
Connolly, Peter and Hazel Dodge; The Ancient City - Life in Classical Athens & Rome, Oxford: Oxford University Press, 1998