Peterborough is a town in Hillsborough County, New Hampshire, United States. The population was 6,284 at the 2010 census. The central settlement in town, with 3,103 people at the 2010 census, is defined as the Peterborough census-designated place and is located along the Contoocook River at the junction of U.S. Route 202 and New Hampshire Route 101. The community is 38 miles west of Manchester and 72 miles northwest of Boston.