Chatham is a town in Barnstable County, Massachusetts, United States. Chatham is located at the southeast tip of Cape Cod and has historically been a fishing community. First settled by the English in 1664, the township was originally called Monomoit based on the indigenous population's term for the region. Chatham was incorporated as a town on June 11, 1712, and has become a summer resort area. The population was 6,594 at the 2020 census, and can swell to 25,000 during the summer months. There are four villages that comprise the town, those being Chatham (CDP), South Chatham, North Chatham, and West Chatham. Chatham is home to the Monomoy National Wildlife Refuge, and the decommissioned Monomoy Point Light both located on Monomoy Island. A popular attraction is the Chatham Light, which is an operational lighthouse that is operated by the United States Coast Guard.

Barnstable County is a county located in the U.S. state of Massachusetts. At the 2020 census, the population was 228,996. Its county seat is Barnstable. The county consists of Cape Cod and associated islands.