Cle Elum Lake is a lake and reservoir along the course of the Cle Elum River, in Washington state USA. Cle Elum Lake is the easternmost lake of three large lakes (two are north and one is south of Interstate 90) in the Cascade Range. The middle one, Kachess Lake is also north of I-90 while the westernmost, Keechelus Lake is south of I-90.

Cle Elum Lake is part of the Columbia River basin, as the Cle Elum River is a tributary of the Yakima River, which is a tributary to the Columbia River.

The lake is used as a storage reservoir for the Yakima Project, an irrigation project run by the United States Bureau of Reclamation. Although a natural lake, Cle Elum Lake's capacity and discharge is controlled by Cle Elum Dam, a 165-foot (50 m) high earthfill structure built in 1933. As a storage reservoir, Cle Elum Lake's active capacity is 436,900 acre feet (539,000,000 m³).

TRIVIA FACT: In 1994, the fictional village of Monanash was filmed on Cle Elum Lake for the TV show Northern Exposure.