Lakes / Montana / Flagstaff Reservoir
Flagstaff Reservoir, Montana
13 acres
Surface Area
5,303.76 ft
Surface Elevation
Where It Sits, and How Deep It Goes
Locator - Montana
46.55 degrees N, 110.53 degrees W - Meagher 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.
How Flagstaff Reservoir Stacks Up
- About 65 miles from Bozeman, as the crow flies.
- 1 fish species on the FWP list for this lake.
Fish Species
Largemouth Bass
Species recorded for this lake. Presence only - no abundance ratings.
Facts and Figures
Waterbody ID78389221
CountyMeagher
Coordinates46.5459, -110.5281
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: Montana Fish, Wildlife & Parks lake data (ID 78389221). Verified October 30, 2026.