Lakes / Oregon / Lake County / Twentymile Slough
Twentymile Slough, Oregon
419 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Oregon
42.13 degrees N, 119.82 degrees W - Lake 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 Twentymile Slough Stacks Up
- Larger than 81% of the 642 lakes counted in Oregon.
- About 153 miles from Bend, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Greaser Reservoir | Lake | 1.3 mi | 65 acres |
| Greaser Lake | Lake | 1.5 mi | 462 acres |
| Greaser Reservoir | Lake | 2.7 mi | 43 acres |
| Greaser Reservoir | Lake | 2.7 mi | 53 acres |
| Coleman Lake | Lake | 4.9 mi | 1,325 acres |
| Horsehead Lake | Lake | 5.3 mi | 149 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Twentymile Slough
How Big Is Twentymile Slough?
Twentymile Slough covers 419 acres in Lake County, Oregon.
What Is the Largest Lake in Lake County?
Lake Abert is the largest lake in Lake County, at 37,137 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 83450897). Verified October 30, 2026.