Lake Chillisquaque, reservoir in Montour County, Pennsylvania, USA

Lake Chillisquaque is a 165-acre reservoir on Middle Branch Chillisquaque Creek in Anthony Township, Montour County, Pennsylvania. It is held back on its south side by the 2,000-foot-long, 54-foot-high Lake Chillisquaque Dam, an earth-fill structure with a silty clay core and weathered shale outer face. The lake has several coves, including Goose Cove, Heron Cove and Jellyfish Cove, and lies within the Montour Preserve.

Lake Chillisquaque was built in 1972 to supply cooling water for the Montour Power Plant. It is owned by the energy company Talen. The reservoir remains in use for cooling and has also become a recreation area within the Montour Preserve.

The name Chillisquaque derives from a Native American term often rendered as "song of the wild goose." More than 50 waterfowl species pass the lake during migration, and about 200 bird species have been recorded on or near it. Visitors can watch geese and other birds from the shoreline or the water.

The lake is reached via Pennsylvania Route 44 and Route 54, with Preserve Road as the nearest access road. The top of the 2,000-foot dam forms an access road on the southern side. Boat ramps and small docks provide water access; only electric motors are allowed, and swimming, alcohol, and firearms are prohibited.

The Montour Preserve surrounding the lake features a fossil pit where visitors can dig in shale and take home fossils they find. A guide book helps identify the discoveries and teaches about the geological history preserved in the Mahantango Formation.