Belchertown is a town in Hampshire County, Massachusetts, United States. It is part of the Springfield, Massachusetts Metropolitan Statistical Area. The population was 15,350 at the 2020 census.

Route 21 is a 13.73-mile-long south–north state highway in Massachusetts that runs between U.S. Route 20 and Route 141 in Springfield and Route 9 in Belchertown. Along the way it intersects several ma