Big Lake is an open body of water surrounded by marshy islands in Navigation Pool 9 of the Upper Mississippi River.

It is part of the Upper Mississippi River National Wildlife and Fish Refuge.

The Army Corps of Engineers maintains the lake's integrity as a fish habitat.

The lake is stocked with rainbow trout twice a year, in October and February.

There is a fishing dock on the lake, and in the surrounding park, there is a playground, walking trails, and a picnic shelter.