Lakes / Idaho / Fremont County / Ashton Reservoir
Ashton Reservoir, Idaho
286.85 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Idaho
44.10 degrees N, 111.49 degrees W - Fremont 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 Ashton Reservoir Stacks Up
- Larger than 76% of the 316 lakes counted in Idaho.
- About 50 miles from Idaho Falls, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Lemon Lake | Fremont | 4.1 mi | 37.56 acres |
| Lower Arcadia Reservoir | Fremont | 5.8 mi | 70.92 acres |
| Upper Arcadia Reservoir | Fremont | 6.3 mi | 42.75 acres |
| Sand Creek Reservoir | Fremont | 9.9 mi | 79.58 acres |
| Beaver Pond | Fremont | 13 mi | 63.26 acres |
| Swan Lake | Fremont | 13 mi | 30.89 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Ashton Reservoir
How Big Is Ashton Reservoir?
Ashton Reservoir covers 286.85 acres in Fremont County, Idaho.
What Is the Largest Lake in Fremont County?
Island Park Reservoir is the largest lake in Fremont County, at 7,550.45 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 120026593). Verified October 30, 2026.