Union Slough National Wildlife Refuge is a 2,200-acre refuge located in Kossuth County, Iowa. The refuge was established in 1938 to provide a breeding ground and refuge for waterfowl and other migratory birds. The slough is all that remains of a pre-glacial riverbed, and its name is derived from the connection of two watersheds: the Blue Earth River of Minnesota and the East Fork of the Des Moines River.