The river Cosson flows through La Ferté-Saint-Aubin watering the castle moats.
After an east-west route of 100 km it flows through Chambord’s park and joins the Beuvron river just before its confluence with that of the Loire.
In the 15th C. a tollgate was set in La Ferté Nabert – the former name of La Ferté-Saint-Aubin – at the crossing of three main roads. Very likely, this tollgate was near the Cosson bridge, protected by the stronghold of La Ferté, the origin of the existing castle.
In 17th C., at the north side, there was a village water-mill powered by mobile locks located under the bridge. An estimate of 1704 mentions those locks to be repared.

Later, around 1865, a village wash-house was built next to the bridge; the former had been laying there until the 1950’s.
The masons used to get sand out of the Cosson and stored it near the bridge, and next to a drinking trough for horses.