Groton is a town in northwestern Middlesex County, Massachusetts, United States, within the Greater Boston metropolitan area. The population was 11,315 at the 2020 census. An affluent bedroom community roughly 45 miles from Boston, Groton has a large population of professional workers, many of whom work in Boston's tech industry. It is loosely connected to Boston by highways and commuter rail. The town has a long history dating back to the colonial era.