Lakes in Union County, Iowa
4 lakes counted in Union County - the largest is Three Mile Lake at 836 acres.
4
Lakes Counted
836 acres
Largest - Three Mile Lake
Union County, highlighted, with its largest counted lakes dotted. Outlines from Census boundary data.
All Counted Lakes
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Three Mile Lake | Union | 836 acres | - |
| 2 | Twelve Mile Lake | Union | 644 acres | - |
| 3 | Green Valley Lake | Union | 330 acres | - |
| 4 | Summit Lake | Union | 105 acres | - |
Sources: USGS National Hydrography Dataset lake data; USGS. Verified October 30, 2026.