Barzy-sur-Marne is located some 15 km east by northeast of Château-Thierry and 35 km southwest of Rheims. It can be accessed on the D320 road from Jaulgonne in the west passing through the commune and the village curving south to Passy-sur-Marne. Apart from the village there are two hamlets: Marcilly, and Rosay both located on the D320 road. Some 70% of the commune in the north is heavily forested with the balance consisting of farmland.[3]
The western border of the commune is formed by the Marne river which flows from the south curving west. One small stream south of the village flows into the Marne.[3]
In the 16th century, the people depended on the Duchess of Vendôme. The three separate hamlets composing the village had once each had a port on the Marne to transport stone.
In 1923 the capital of the commune of Barzy-sur-Marne was transferred from Barzy-sur-Marne to the hamlet of Marcilly which became the capital of the commune but this transfer was done without changing the name of the commune following the Decree of 23 October 1923.[4]
