| Lake Mayfield | |
|---|---|
| Location | Lewis County, Washington, USA |
| Lake type | reservoir |
| Primary inflows | Cowlitz River, Tilden River |
| Primary outflows | Cowlitz River |
| Basin countries | United States |
| Islands | 1, Harold Freece Island |
Lake Mayfield is a reservoir located near Mossyrock, Washington, in Lewis County. It was created by Mayfield Dam on the Cowlitz River. The lake contains an island with a lighthouse.
The Cowlitz River Arm is significantly colder than the rest of the lake due to its proximity to the Riffe Lake which is created by 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. The Tilton River area is often referred to as 'Wally World'.
Throughout the 1980s and 90s there were many water ski and wake board tournaments held on the lake's Winston Creek arm where the Lake Mayfield Resort was located.