Hinsdale is a town in Cheshire County, New Hampshire, United States. The population was 4,082 at the 2000 census. Hinsdale is home to part of Pisgah State Park in the northeast, and part of Wantastiquet Mountain State Forest in the northwest. The oldest continually-operating post office in the United States, established in 1816, is located on Main Street in Hinsdale. The primary settlement in town, where over 41% of the population resides, is defined as the Hinsdale census-designated place (CDP), and is located at the junction of New Hampshire Routes 63 and 119.