Glenville is a neighborhood and census-designated place in the town of Greenwich in Fairfield County, Connecticut, United States.

[2] It is located in the western part of Greenwich at the falls of the Byram River, which provided waterpower when this was a mill village.

Of these neighborhoods, three (Cos Cob, Old Greenwich, and Riverside) have separate postal names and ZIP codes.

The district covers 33.9 acres (13.7 ha) and is the "most comprehensive example of a New England mill village within the Town of Greenwich".

"[3] According to the United States Census Bureau, the CDP has a total area of 0.739 square miles (1.91 km2), all land.