Lake Youngs is a reservoir in King County, Washington, United States.

It is located between Maple Valley and Renton along the route of pipelines carrying water from the Cedar River to Seattle (the most recent of these is the Bow Lake pipeline, which was built in 1954[1][2]) and is accessible only to Seattle Public Utilities staff and authorized visitors.

Lake Youngs has a surface area of 700 acres (2.8 km2) and a maximum depth of 72 feet (22 m).

[4] It was named for longtime Seattle Water Department head L. B. Youngs, who died in 1923.

[2] Lake Youngs is used as a visual checkpoint for pilots flying into and out of Renton Municipal Airport.