is a town in New London County, Connecticut, United States. The population was 14,551 at the 2000 census. In 2005, it was ranked 57th on the "100 Best Places to Live", conducted by CNN. Colchester is one of the fastest growing towns in Connecticut. The villages of Westchester and North Westchester are located within Colchester, as is the reservation of the Golden Hill Paugussett Indian Nation.
According to the United States Census Bureau, the town has a total area of 49.8 square miles (129.0 km²), of which, 49.1 square miles (127.1 km²) of it is land and 0.7 square miles (1.9 km²) of it (1.49%) is water.