Lakes / Montana / Cornwell Reservoir
Cornwell Reservoir, Montana
43.5 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Montana
48.38 degrees N, 106.71 degrees W - Valley County. State and county outlines drawn from Census boundary data; the lake marker is placed by its Montana Fish, Wildlife & Parks coordinates, not by eye. Schematic - not a survey map.
Facts and Figures
Waterbody ID146571226
CountyValley
Coordinates48.3775, -106.7127
Largest Lakes in Montana
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Fort Peck Lake | Valley | 233,053 acres | - |
| 2 | Flathead Lake | Lake | 122,132 acres | About 380 ft |
| 3 | Canyon Ferry Lake | Broadwater | 32,773 acres | About 170 ft |
| 4 | Lake Koocanusa | Lincoln | 28,723 acres | - |
| 5 | Hungry Horse Reservoir | Flathead | 23,577 acres | - |
Sources: USGS NHD lake data (ID 146571226). Verified October 30, 2026.