Johnstown is located in Fulton County 53 miles west of Saratoga Springs between Gloversville and Fonda along Highway 30/30A near Great Sacandaga Lake in the Northern Region of the state. The famous women's rights advocate Elizabeth Cady Staton was born here in 1815.

The city was named after John Johnson, son of Sir William Johnson, political figure who settled here in 1762. It was the setting for Richard Russo's novel, "Mohawk" and Robert Moss's "The Firekeeper".