Wilmington is a town in Windham County, Vermont, United States. The population was 2,255 at the 2020 census. The town was chartered in 1751 by Benning Wentworth, colonial governor of New Hampshire. It was named in honor of Spencer Compton, 1st Earl of Wilmington. Wilmington is the home of Haystack Mountain Ski Area, which operates as the pr…Wilmington is a town in Windham County, Vermont, United States. The population was 2,255 at the 2020 census. The town was chartered in 1751 by Benning Wentworth, colonial governor of New Hampshire. It was named in honor of Spencer Compton, 1st Earl of Wilmington. Wilmington is the home of Haystack Mountain Ski Area, which operates as the private Hermitage Club.