Stonington is a town located in New London County, Connecticut. The municipal limits of the town include the borough of Stonington, the villages of Pawcatuck, Lords Point, and Wequetequock, and the eastern halves of the villages of Mystic and Old Mystic. Stonington is part of the Southeastern Connecticut Planning Region. The population of the town was 18,335 at the 2020 census.

New London County is in the southeastern corner of Connecticut and comprises the Norwich-New London, Connecticut Metropolitan Statistical Area, which is also included in the Hartford-East Hartford, Connecticut Combined Statistical Area. There is no county government and no county seat, as is the case with all eight of Connecticut's counties; towns are responsible for all local government activities, including fire and rescue, snow removal, and schools.