Lakes / Oregon / Harney County / Threemile Reservoir
Threemile Reservoir, Harney County, Oregon
168 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Oregon
42.49 degrees N, 118.91 degrees W - Harney 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 Threemile Reservoir Stacks Up
- Larger than 69% of the 642 lakes counted in Oregon.
- About 162 miles from Bend, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| West Field Lake | Harney | 2.7 mi | 132 acres |
| Garrison Lake | Harney | 5.7 mi | 528 acres |
| V Lake | Harney | 8.4 mi | 31 acres |
| Skull Creek Reservoir | Harney | 10 mi | 75 acres |
| Bradley Lake | Harney | 12 mi | 25 acres |
| Alvord Lake | Harney | 17 mi | 3,648 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Threemile Reservoir
How Big Is Threemile Reservoir?
Threemile Reservoir covers 168 acres in Harney County, Oregon.
What Is the Largest Lake in Harney County?
Harney Lake is the largest lake in Harney County, at 31,290 acres.
Largest Lakes in Oregon
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Upper Klamath Lake | Klamath | 62,095 acres | - |
| 2 | Lake Umatilla | Morrow | 50,042 acres | - |
| 3 | Lake Abert | Lake | 37,137 acres | - |
| 4 | Summer Lake | Lake | 31,602 acres | - |
| 5 | Harney Lake | Harney | 31,290 acres | - |
All 642 Oregon lakes ranked by surface area
Sources: USGS NHD (The National Map NHD MapServer layer 12) named waterbodies FTYPE 390/436; counties via Census point-in-polygon lake data (ID 158122686). Verified October 30, 2026.