Lakes / Montana / Rosebud County
Lakes in Rosebud County, Montana
18 lakes counted in Rosebud County - the largest is Castle Rock Lake at 155 acres.
18
Lakes Counted
155 acres
Largest - Castle Rock Lake
Rosebud County, highlighted, with its largest counted lakes dotted. Outlines from Census boundary data.
All Counted Lakes
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Castle Rock Lake | Rosebud | 155 acres | About 40 ft |
| 2 | Kerns Reservoir | Rosebud | 125 acres | - |
| 3 | Black Sea Reservoir | Rosebud | 66 acres | - |
| 4 | Brown Coulee Reservoir | Rosebud | 63.5 acres | - |
| 5 | Zempel Lake | Rosebud | 62.4 acres | - |
| 6 | Blacktail Reservoir | Rosebud | 57.6 acres | - |
| 7 | Stellar Lake | Rosebud | 49.9 acres | - |
| 8 | Thebes Lake | Rosebud | 47.9 acres | - |
| 9 | Blacktail Reservoir | Rosebud | 45.5 acres | - |
| 10 | Zempel Lake | Rosebud | 39.2 acres | - |
| 11 | Donleys Reservoir | Rosebud | 39 acres | - |
| 12 | Barley Reservoir | Rosebud | 36.6 acres | - |
| 13 | Boies Reservoir | Rosebud | 30.4 acres | - |
| 14 | Barley Reservoirs | Rosebud | 29.4 acres | - |
| 15 | Black Sea Reservoir | Rosebud | 27.6 acres | - |
| 16 | Boyce Reservoir | Rosebud | 5 acres | - |
| 17 | Red Rock Reservoir Number One | Rosebud | 2 acres | - |
| 18 | Poker Jim Reservoir | Rosebud | 1 acres | - |
Sources: Montana Fish, Wildlife & Parks lake data; USGS. Verified October 30, 2026.