Mystic is a village and census-designated place (CDP) in New London County, Connecticut, in the United States. The population was 4,205 at the 2010 census. Mystic has no independent government because it is not a legally recognized municipality in the state of Connecticut. Rather, Mystic is located within the towns of Groton (west of the Mystic River, and also known as West Mystic) and Stonington (east of the Mystic River).