| Big Lake | |
|---|---|
| (United States Environmental Protection Agency) | |
| Location | Allamakee County, Iowa |
| Lake type | Reservoir |
| Primary inflows | Upper Mississippi River |
| Primary outflows | Upper Mississippi River |
| Basin countries | United States |
Big Lake is an open body of water surrounded by marshy islands in Navigation Pool 9 of the Upper Mississippi River. It lies where the Iowa, Minnesota and Wisconsin borders come together, just north of Lansing, Iowa. It is part of the Upper Mississippi River National Wildlife and Fish Refuge.
The Army Corps of Engineers maintains the lake's integrity as fish habitat.