Lakes / Washington / Lake Merwin
Lake Merwin, Washington
3,837 acres
Surface Area
237 ft
Surface Elevation
Where It Sits, and How Deep It Goes
Locator - Washington
45.97 degrees N, 122.45 degrees W - Clark 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 Lake Merwin Stacks Up
- The largest lake in Clark County among those counted.
- About 77 miles from Olympia, as the crow flies.
- 7 fish species on the WDFW list for this lake.
Fish Species
Bull troutChinook salmonCoho salmonKokaneeNorthern pikeminnowTiger muskieRainbow trout
Species recorded for this lake. Presence only - no abundance ratings.
Facts and Figures
Waterbody ID129397559
CountyClark
Lake TypeLake
Coordinates45.9732, -122.4466
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 129397559). Verified October 30, 2026.