Belchertown is a town in Hampshire County, Massachusetts, United States. The population was 12,968 at the 2000 census. It is the home of Belchertown High School, and the infamous Belchertown State School mental institution Belchertown apartments for rent comparison page shows most up to date rent information on Belchertown apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.