Dunbarton is a town in Merrimack County, New Hampshire, United States. The population was 3,005 at the 2020 census, up from 2,758 at the 2010 census. Originally granted as "Gorham's-town" in 1735, and re-granted as "Starkstown" in 1748, the town was incorporated in 1765 as Dunbarton. The name came from Dunbartonshire in Scotland, hometown to Archiā¦Dunbarton is a town in Merrimack County, New Hampshire, United States. The population was 3,005 at the 2020 census, up from 2,758 at the 2010 census. Originally granted as "Gorham's-town" in 1735, and re-granted as "Starkstown" in 1748, the town was incorporated in 1765 as Dunbarton. The name came from Dunbartonshire in Scotland, hometown to Archibald Stark, a prominent settler.