St. Johnsville is a town in Montgomery County, New York, United States.

Accounts vary as to the etymology of St. Johnsville, but most of them state that the town and its village are named after an early surveyor and commissioner, Alexander St.

The Erie Canal, as part of the Mohawk River, is at the town's southern border.

In 1769, Sir William Johnson built a church in the town for the benefit of his Indian allies.

According to the Enterprise and News, November 17, 1937, by 1934, Mr. and Mrs. Joseph H. Reaney had given 120 acres of land to the Village of Saint Johnsville.

Today the H.C Smith Benefit Club utilizes the building to host many community events.

The First Methodist Episcopal Church of St. Johnsville, Fort Klock, Enlarged Double Lock No.

33 Old Erie Canal, Nellis Tavern, and Margaret Reaney Memorial Library are listed on the National Register of Historic Places.