Suffield is a town in Hartford County, Connecticut, United States. It had once been within the boundaries of Massachusetts. The town is located in the Connecticut River Valley with the town of Enfield neighboring to the east. In 1900, 3,521 people lived in Suffield; and in 1910, 3,841. The population was 13,552 at the 2000 census. The town center was designated as a census-designated place known as Suffield Depot in the 2000 census.