is a town in Hartford County, Connecticut, United States. It had once been within the boundaries of Massachusetts. 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.
According to the United States Census Bureau, the town has a total area of 42.9 square miles (111.2 km²), of which 42.2 sq mi (109.3 km²) is land and 0.7 sq mi (1.9 km² or 1.68%) is water. The town center (Suffield Depot CDP) has a total area of 2.0 square miles (5.1 km
Suffield is on the west bank of the Connecticut River, north of Hartford, Connecticut. Two bridges span the river to the town of Enfield: the Amtrak/Springfield Terminal Railroad Bridge and the Enfield-Suffield Veterans Bridge.
The Metacomet Ridge, a mountainous traprock ridgeline that stretches from Long Island Sound to nearly the Vermont border, runs through the center of Suffield from south to north as West Suffield Mountain. The Metacomet Trail traverses the ridge.