Haverhill is a town in Grafton County, New Hampshire, United States. The population was 4,697 at the 2010 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. The village of North Haverhill is the county seat of Grafton County.