Lakes / Montana / Upper Grinnell Lake
Upper Grinnell Lake, Montana
100.6 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Montana
48.76 degrees N, 113.73 degrees W - Flathead 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 ID136325083
CountyFlathead
Coordinates48.7570, -113.7310
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 136325083). Verified October 30, 2026.