Wethersfield is a town in Hartford County, Connecticut, United States. It is located immediately south of Hartford along the Connecticut River. Its population was 26,668 in the 2010 census.Many records from colonial times spell the name "Weathersfield", while Native Americans called it "Pyquag". "Watertown" is a variant name.The town is primarily served by Interstate 91. The neighborhood known as Old Wethersfield is the state's largest historic district, spanning 2 sq mi and 1,100 buildings, dating back to the 17th, 18th and 19th centuries.