Grafton County is a county in the U.S. state of New Hampshire. As of the 2020 census, the population was 91,118. Its county seat is the town of Haverhill. In 1972, the county courthouse and other offices were moved from Woodsville, a larger village within the town of Haverhill, to North Haverhill.

Haverhill is a town and the seat of Grafton County, New Hampshire, United States. The population was 4,585 at the 2020 census. Haverhill includes the villages of Woodsville, Pike, and North Haverhill, the historic town center at Haverhill Corner, and the district of Mountain Lakes. Located here are Bedell Bridge State Park, Black Mountain State Forest, Kinder Memorial Forest, and Oliverian Valley Wildlife Preserve. It is home to the annual North Haverhill Fair, and to a branch of the New Hampshire Community Technical Colleges.