Southport is a census-designated place in the town of Fairfield, Connecticut. It is located along Long Island Sound between Mill River and Sasco Brook, where it borders Westport. As of the 2010 census, it had a population of 1,585. Settled in 1639, Southport center has been designated a local historic district since 1967, and was listed on the National Register of Historic Places in 1971 as the Southport Historic District.