Ridgefield is a town in Fairfield County, Connecticut, United States. Situated in the foothills of the Berkshire Mountains and on the New York state border, Ridgefield had a population of 25,033 as of the 2020 census. The town is part of the Western Connecticut Planning Region. The town center, which was formerly a borough, is defined by the U.S. Census Bureau as a census-designated place. The town was settled then quickly incorporated by 1709.