Harpswell is a town in Cumberland County, Maine, United States, within Casco Bay in the Gulf of Maine. The population was 4,740 at the 2010 census. Harpswell is composed of land contiguous with the rest of Cumberland County, called Harpswell Neck, as well as three large islands connected by bridges: Sebascodegan Island (locally known as Great Island), Orr's Island, and Bailey Island and over 200 smaller islands. Harpswell is part of the Portland–South Portland–Biddeford, Maine Metropolitan Statistical Area.
The Native Americans who originally inhabited Harpswell were part of the Abenaki. The Abenaki name for Harpswell Neck, then called West Harpswell, was Merriconeag or "quick carrying place", a reference to the narrow peninsula's easy portage. The Abenaki name for Great Island was Erascohegan or Sebascodiggin, which became by the late 1800s Sebascodegan Island. About 1659 Major Nicholas Shapleigh of Kittery, Maine, bought Merriconeag and Sebascodegan Island from the Abenaki, but because of Indian attacks, attempts to settle the area were abandoned until after Dummer's War. The Treaty of 1725 brought a truce, and by 1731 many settlers had returned.
Formerly a part of North Yarmouth, in 1758 the town was incorporated by the Massachusetts General Court and named for Harpswell in Lincolnshire, England. Industries included farming and some shipbuilding, but fishing brought considerable profit, and lobstering is still a thriving part of the economy.