Lake Mills was a reservoir in Olympic National Park, Washington, United States, that existed from 1927 to 2012. It was formed by the Glines Canyon Dam on the Elwha River and was located about 13 miles from the mouth of the river on the Olympic Peninsula. The lake was formed in 1927 with the completion of the dam and after the lowland forest that occupied the river bottom was clear-cut. With no fish passage facilities, the dam blocked passage of anadromous Pacific Salmon from the upper 50+ miles of the Elwha watershed located within Olympic National Park.