Lakes / Illinois / Williamson County / Little Grassy Lake
Little Grassy Lake, Illinois
905.39 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Illinois
37.63 degrees N, 89.14 degrees W - Williamson 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 Little Grassy Lake Stacks Up
- Larger than 91% of the 511 lakes counted in Illinois.
- About 8 miles from Carbondale, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Spring Arbor Lake | Jackson | 1.8 mi | 66.47 acres |
| Devils Kitchen Lake | Williamson | 2.9 mi | 711.91 acres |
| Carbondale Reservoir | Jackson | 6.6 mi | 126.27 acres |
| Crab Orchard Lake | Williamson | 6.8 mi | 7,292.57 acres |
| Herrin Lake | Williamson | 7.0 mi | 52.39 acres |
| Campus Lake | Jackson | 7.2 mi | 41.27 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Little Grassy Lake
How Big Is Little Grassy Lake?
Little Grassy Lake covers 905.39 acres in Williamson County, Illinois.
What Is the Largest Lake in Williamson County?
Crab Orchard Lake is the largest lake in Williamson County, at 7,292.57 acres.
Largest Lakes in Illinois
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Carlyle Lake | Clinton | 22,796.77 acres | - |
| 2 | Mine Number 21 Reservoir | Franklin | 17,062.04 acres | - |
| 3 | Upper Peoria Lake | Woodford | 15,460.64 acres | - |
| 4 | Lake Shelbyville | Shelby | 10,235.1 acres | - |
| 5 | Crab Orchard Lake | Williamson | 7,292.57 acres | - |
All 511 Illinois lakes ranked by surface area
Sources: USGS National Hydrography Dataset (The National Map) lake data (ID 48812990). Verified October 30, 2026.