Lakes / Idaho / Custer County / Mosquito Flat Reservoir
Mosquito Flat Reservoir, Idaho
49.13 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Idaho
44.52 degrees N, 114.44 degrees W - Custer 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 Mosquito Flat Reservoir Stacks Up
- Larger than 35% of the 316 lakes counted in Idaho.
- About 58 miles from Ketchum, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Sullivan Lake | Custer | 20 mi | 40.53 acres |
| Jimmy Smith Lake | Custer | 24 mi | 62.76 acres |
| Quiet Lake | Custer | 33 mi | 27.43 acres |
| Little Redfish Lake | Custer | 34 mi | 63.77 acres |
| Bear Valley Lakes | Lemhi | 34 mi | 28.15 acres |
| Cape Horn Lakes | Custer | 35 mi | 31.38 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Mosquito Flat Reservoir
How Big Is Mosquito Flat Reservoir?
Mosquito Flat Reservoir covers 49.13 acres in Custer County, Idaho.
What Is the Largest Lake in Custer County?
Redfish Lake is the largest lake in Custer County, at 1,503.88 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 39262672). Verified October 30, 2026.