The lake is [convert: invalid number] deep at its deepest point, with a mean depth of 1,200 feet (370 m).

[3] It is in Cumberland County, and bordered by the towns of Casco, Naples, Raymond, Sebago, Standish and Windham.

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.

A Grumman TBF Avenger from the Lewiston Naval Auxiliary Air Facility ditched and sank near Raymond on 16 August 1943.

The lake's watershed is more than 50 miles (80 km) long and covers parts of 24 Maine towns.

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.

The park now consists of 1,400 acres (5.7 km2), is open year-round, and has facilities including two public boat launches, an expansive natural sandbar for swimming, and a 250-site campground.

The lake is the likely point of origin of the landlocked salmon, stated in the species' scientific name (Salmo salar sebago).

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.