Errol is a town in Coös County, New Hampshire, United States. The population was 298 at the 2020 census. It is located north of the White Mountains along Route 16 at its intersection of Route 26. It has a municipal airport with a single, unpaved runway.

Coös County or Coos County is a county in the U.S. state of New Hampshire. As of the 2020 census, the population was 31,268, making it the least-populated county in the state. The county seat is Lancaster.