Alton is a town in Belknap County, New Hampshire, United States. The population was 5,894 at the 2020 census, up from 5,250 at the 2010 census. It is home to Alton Bay State Forest and Mount Major State Forest.

Belknap County is a county in the U.S. state of New Hampshire. As of the 2020 census, the population was 63,705. The county seat is Laconia. It is located in New Hampshire's Lakes Region, slightly southeast of the state's geographic center. Belknap County comprises the Laconia, NH Micropolitan Statistical Area, which in turn constitutes a portion of the Boston-Worcester-Providence, MA-RI-NH-CT Combined Statistical Area.