Hopkinton is a town in Merrimack County, New Hampshire, United States. The population was 5,589 at the 2010 census. The town has three distinct communities: Hopkinton village, mainly a residential area in the center of the town; Contoocook, the town's business hub, located in the north; and West Hopkinton, within the more agricultural portion of the town. The town is home to the Hopkinton State Fair, adjacent to Contoocook village, and to the historic Contoocook Railroad Depot and the Contoocook Railroad Bridge, the oldest covered railroad bridge in the United States.