Lakes / Illinois / Grundy County
Lakes in Grundy County, Illinois
3 lakes counted in Grundy County - the largest is Heidecke Lake at 1,913.34 acres.
3
Lakes Counted
1,913.34 acres
Largest - Heidecke Lake
Grundy County, highlighted, with its largest counted lakes dotted. Outlines from Census boundary data.
All Counted Lakes
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Heidecke Lake | Grundy | 1,913.34 acres | - |
| 2 | Goose Lake | Grundy | 40.53 acres | - |
| 3 | Negro Slough | Grundy | 26.69 acres | - |
Sources: USGS National Hydrography Dataset lake data; USGS. Verified October 30, 2026.