Lyman is a town in Grafton County, New Hampshire, United States. The population was 585 at the 2020 census. Lyman, along with Grantham, Lisbon, and eleven Vermont towns, was granted as compensation to General Phineas Lyman, a commander in the French and Indian War. According to the county gazetteer, "It was granted to Daniel Lyman a…Lyman is a town in Grafton County, New Hampshire, United States. The population was 585 at the 2020 census. Lyman, along with Grantham, Lisbon, and eleven Vermont towns, was granted as compensation to General Phineas Lyman, a commander in the French and Indian War. According to the county gazetteer, "It was granted to Daniel Lyman and sixty-three others, November 10, 1761, its name being derived from the fact that eleven of the grantees bore the name of Lyman. The grantees failed to comply with the requirements of their charter, and thus forfeited their grant, but an extension of time was granted them July 20, 1769." Until 1854, Lyman included the land which is now Monroe, New Hampshire, but it was split due to the difficulty in traversing Gardner Mountain which formerly bisected the town. In 1880 it had a population of 665.