Lake Crescent, Glacial lake in Olympic National Park, United States.

Lake Crescent is a deep lake in Olympic National Park, about 17 miles west of Port Angeles on U.S. Route 101. Its official maximum depth is 624 feet (190 m), the second deepest in Washington; a 2013–2014 bathymetric survey measured 596 feet (182 m). The water appears deep blue in the center and lighter blue-green near the shore, where gray rocks sit partly submerged below forested hillsides.

The lake basin formed during the last Ice Age through glacier carving, and approximately 8,000 years ago a mountain slide blocked Indian Creek and flooded the valley. These two geological events shaped the body of water we see today.

The lake is home to two distinct trout varieties that developed in isolation after water separated their populations, and these species remain important to people who fish here today.

Multiple access points and recreational areas are spread along the shoreline, with the Spruce Railroad Trail offering a popular walking path and places to swim. Spring through fall provides the most comfortable conditions for outdoor activities here.

In 1929 Russell and Blanch Warren vanished while driving near the lake; their 1927 Chevrolet was only located in 2002, more than 160 feet (49 m) below the surface. The near-freezing water also preserved the body of waitress Hallie Illingworth, missing since 1937 and found by fishermen three years later.