Lakes / Washington / Mason Lake
Mason Lake, King County, Washington
31 acres
Surface Area
4,174 ft
Surface Elevation
Where It Sits, and How Deep It Goes
Locator - Washington
47.42 degrees N, 121.55 degrees W - King County. State and county outlines drawn from Census boundary data; the lake marker is placed by its Washington DFW coordinates, not by eye. Schematic - not a survey map.
How Mason Lake Stacks Up
- About 39 miles from Seattle, as the crow flies.
- 1 fish species on the WDFW list for this lake.
Fish Species
Rainbow trout
Species recorded for this lake. Presence only - no abundance ratings.
Facts and Figures
Waterbody ID129061374
CountyKing
Lake TypeLake
Coordinates47.4236, -121.5512
Largest Lakes in Washington
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Franklin D Roosevelt Lake | Ferry | 71,323 acres | - |
| 2 | Lake Umatilla | Klickitat | 50,042 acres | - |
| 3 | Lake Chelan | Chelan | 32,677 acres | About 1,500 ft |
| 4 | Banks Lake | Grant | 26,879 acres | - |
| 5 | Lake Wallula | Benton | 26,343 acres | - |
Sources: Washington DFW; USGS NHD via WA Dept of Ecology lake data (ID 129061374). Verified October 30, 2026.