Alstead is a town in Cheshire County, New Hampshire, United States. The population was 1,864 at the 2020 census. Alstead is home to Feuer State Forest.

New Hampshire Route 12 is a 62.773-mile (101.023 km) long north–south state highway in southwestern New Hampshire. Its southern terminus is at the Massachusetts state line in Fitzwilliam, where it continues south as Massachusetts Route 12. Its northern terminus is at the Vermont state line in Claremont, where it continues north as Vermont Route 12. Most of the northern part of NH 12 runs along the Connecticut River.