Lakes / Idaho / Owyhee County / Grasmere Reservoir
Grasmere Reservoir, Idaho
29.18 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Idaho
42.36 degrees N, 115.91 degrees W - Owyhee County. State and county outlines drawn from Census boundary data; the lake marker is placed by its USGS National Hydrography Dataset coordinates, not by eye. Schematic - not a survey map.
How Grasmere Reservoir Stacks Up
- Larger than 6% of the 316 lakes counted in Idaho.
- About 75 miles from Twin Falls, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Payne Creek Reservoir | Owyhee | 11 mi | 71.91 acres |
| Little Blue Creek Reservoir | Owyhee | 12 mi | 133.44 acres |
| Tindall Reservoir | Owyhee | 12 mi | 32.08 acres |
| Big Blue Creek Reservoir | Owyhee | 15 mi | 185.58 acres |
| Sage Hen Reservoir | Owyhee | 15 mi | 45.85 acres |
| Dry Lake | Owyhee | 17 mi | 38.8 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Grasmere Reservoir
How Big Is Grasmere Reservoir?
Grasmere Reservoir covers 29.18 acres in Owyhee County, Idaho.
What Is the Largest Lake in Owyhee County?
C J Strike Reservoir is the largest lake in Owyhee County, at 6,207.99 acres.
Largest Lakes in Idaho
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Lake Pend Oreille | Bonner | 92,764.44 acres | - |
| 2 | American Falls Reservoir | Power | 55,319.78 acres | - |
| 3 | Coeur d'Alene Lake | Kootenai | 26,891.64 acres | - |
| 4 | Lake Cascade | Valley | 25,043.4 acres | - |
| 5 | Priest Lake | Bonner | 23,425.59 acres | - |
All 316 Idaho lakes ranked by surface area
Sources: USGS National Hydrography Dataset (The National Map) lake data (ID 128099028). Verified October 30, 2026.