Sebago Lake is the deepest and second largest lake in the U.S. state of Maine. The lake is 316ft deep at its deepest point, with a mean depth of 101ft, covers about 45sqmi in surface area, has a length of 12mi and a shoreline length of 105mi. The surface is around 270ft above sea level, so the deep bottom is below the present sea level. It is located in Cumberland County, Maine, and bordered by the towns of Casco, Naples, Raymond, Sebago, Standish and Windham. The seasonally occupied town of Frye Island is on an island in the lake.TransportationThe lake is connected to Brandy Pond by the Songo River and eventually to Long Lake in Naples. The name comes from a local Native American tribe. The lake is drained primarily by the Presumpscot River. The lake and rivers were an early transportation corridor from the coast to the interior, and encouraged the first incorporated European settlement of interior Maine in 1762. Sebago Lake was linked to Portland harbor by the Cumberland and Oxford Canal in 1832. The outlet to the Presumpscot River was controlled for the canal by the Eel Weir Dam and the Head Dam, owned and operated by the Oriental Powder Company after the canal was replaced by a railroad and by the S. D. Warren Paper Mill after 1878.