Lake Mayfield is a reservoir located near Mossyrock, Washington, in Lewis County.

At 250 feet (76 m) high and capable of generating 162 megawatts, it supplies Tacoma Power with a large percentage of its entire hydroelectric power supply, second only to Mossyrock Dam.

The water from Riffe Lake flows through the Mossyrock Powerhouse's two hydroelectric generators.

The Tilton River arm is much warmer and shallower due to past landslides.

Tiger muskies were introduced in 1993 to help control northern pikeminnow (squawfish) populations.