Lakes / Illinois / Cass County
Lakes in Cass County, Illinois
4 lakes counted in Cass County - the largest is Treadway Lake at 1,477.8 acres.
4
Lakes Counted
1,477.8 acres
Largest - Treadway Lake
Cass County, highlighted, with its largest counted lakes dotted. Outlines from Census boundary data.
All Counted Lakes
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Treadway Lake | Cass | 1,477.8 acres | - |
| 2 | Meyers Pond | Cass | 147.03 acres | - |
| 3 | Swamp Slough | Cass | 31.63 acres | - |
| 4 | Finger Lake | Cass | 27.43 acres | - |
Sources: USGS National Hydrography Dataset lake data; USGS. Verified October 30, 2026.