Charlton is a town in Worcester County, Massachusetts, United States. The population was 13,315 at the 2020 census. Charlton was first settled in 1735. It was established as a District separated from Oxford on January 10, 1755, and became a Town on August 23, 1775, by a law that made all Districts into Towns to help for the cause of the Revolutionary War. It …Charlton is a town in Worcester County, Massachusetts, United States. The population was 13,315 at the 2020 census. Charlton was first settled in 1735. It was established as a District separated from Oxford on January 10, 1755, and became a Town on August 23, 1775, by a law that made all Districts into Towns to help for the cause of the Revolutionary War. It was named after Sir Francis Charlton. During the 1800s, farming continued to be the major occupation, but woolen mills were being built along some of the town's brooks by the turn of the twentieth century.