Lakes in Gem County, Idaho
2 lakes counted in Gem County - the largest is Black Canyon Reservoir at 876.47 acres.
2
Lakes Counted
876.47 acres
Largest - Black Canyon Reservoir
Gem County, highlighted, with its largest counted lakes dotted. Outlines from Census boundary data.
All Counted Lakes
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Black Canyon Reservoir | Gem | 876.47 acres | - |
| 2 | Sage Hen Reservoir | Gem | 237.6 acres | - |
Sources: USGS National Hydrography Dataset lake data; USGS. Verified October 30, 2026.