Sebago Lake is the deepest and second-largest lake in the U.S. state of Maine. The lake is deep at its deepest point, with a mean depth of, covers about in surface area, has a length of and has a shoreline length of roughly. The surface is around above sea level, so the deep bottom is below the present sea level. It is in Cumberland County, 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. Sebago Lake and the surrounding area is known for its erratic and sudden changes in weather during all seasons, likely due to its proximity to the Atlantic Ocean and to Mt. Washington, a very notorious extreme weather hotspot. Sebago means "big still water" in Abenaki.
Transportation
The 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. The lake was a comparatively safe place for training military pilots from NAS Brunswick about flying over water; but several navy planes were lost over the lake during World War II. A Grumman TBF Avenger from the Lewiston Naval Auxiliary Air Facility ditched and sank near Raymond on 16 August 1943. Two low-flying British Vought Corsairs from Brunswick were lost after a mid-air collision over the lake near Raymond on 16 May 1944; and a third Corsair flew into the lake on July 16. In December 2014 the first Sebago Lake beach landing in the history of the world was made by a yellow Supercub.
Water supply
Sebago Lake is the primary water supply for the Portland Water District, which serves the Greater Portland region and about 20% of Maine's population. The lake's watershed is more than long and covers parts of 24 Maine towns. The lake holds roughly of water that on average resides 5.1 to 5.4 years in the lake. The direct watershed is about of land plus the of the lake, and the indirect watershed about of land plus about of other bodies of water. As of May 1990, roughly 86% of the watershed was forests and fallow fields, 2.5% in active timber operations, 9.3% in residential, agricultural, and commercial use, and 2.2% used for other purposes. Water inflow is estimated at per day and outflow at per day, of which /day are for the water district.
Recreation
In 1938, Maine opened Sebago Lake State Park as one of its original five state parks. The area was a recreation center even before this. The park is now , open year-round, and has facilities including two public boat launches and a 250-site campground. There are also numerous private campgrounds, cottages, and other recreational facilities in the area. Although the lake has many Public access sites, it is becoming increasingly difficult to access the lake by land or water for recreation due to new private developments taking over much of its shoreline. As a result, a vast majority of the lake's shoreline is private property or is otherwise off-limits to land-based recreation. Sebago Lake hosts a sailing instruction and charter service and is located in what Maine's tourism industry refers to as the Western Lakes and Mountains Region. Efforts are underway to complete the Sebago to the Sea Trail, a trail running 28 miles from Sebago Lake to Casco Bay, mostly following the path of the Presumpscot River.
Fishing
The lake is the likely point of origin of the landlocked salmon, stated in the species' scientific name. At one point, the entire watershed was under seawater, and the first populations of these marine animals became established as the land rose and seawaters retreated. Other game fish that can be found in the lake include lake trout, brook trout, brown trout, largemouth bass, and northern pike. Some of these are stocked by the state, either in the lake directly or in connected bodies of water, while others were introduced illegally. The state encourages anglers to kill, hold, and notify them of all northern pike taken in the lake because they were introduced illegally, are not native to the region, and could disrupt the lake ecosystem, including that of Sebago Lake's original fish species, such as the landlocked salmon.
Camp
, a day camp run by the Jewish Community Alliance of Southern Maine, is located on the shores of Sebago Lake. Camp O-At-Ka, founded in 1906, is located along a half mile of waterfront in the northwest corner of Sebago Lake. Camp Sebago, a camp run by The Salvation Army is located on the southwestern corner of Sebago Lake. Camp Wohelo, the original Camp Fire Girls camp was established on Sebago Lake in 1907. Founded by Luther Halsey Gulick and Charlotte Vetter Gulick, known by their native American names of Timanous and Hiitini, the camp strove to teach independence and back woods skills to young girls aged 6–16. Wohelo is still strong today.
