Lakes / Illinois / Marion County / Forbes Lake
Forbes Lake, Illinois
523.37 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Illinois
38.72 degrees N, 88.76 degrees W - Marion 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 Forbes Lake Stacks Up
- Larger than 87% of the 511 lakes counted in Illinois.
- About 73 miles from Carbondale, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Greendale Lake | Clay | 6.1 mi | 43.49 acres |
| C and EI Reservoir | Marion | 11 mi | 45.96 acres |
| Patterson Lake | Clay | 11 mi | 28.91 acres |
| Salem Reservoir | Marion | 11 mi | 65.48 acres |
| Sam Dale Lake | Wayne | 16 mi | 209.79 acres |
| Lake Centralia | Marion | 17 mi | 249.58 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Forbes Lake
How Big Is Forbes Lake?
Forbes Lake covers 523.37 acres in Marion County, Illinois.
What Is the Largest Lake in Marion County?
Centralia Reservoir is the largest lake in Marion County, at 645.08 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 149783252). Verified October 30, 2026.