Important Bird Area.
At 5,685 acres (8.9 sq. mi.), Big Spirit Lake is Iowa's natural lake, formed by the retreating Des Moines Lobe of the Wisconsinian Glacier about 12.000 years ago. Although very large, it is relatively shallow (26 ft. at greatest depth).

Immediately north of the City of Spirit Lake, in northern Dickinson County. Accessible from all sides by paved roads, state parks, wildlife areas and boat launch sites. Open water lake, with some emergent vegetation along the eastern and northeastern shorelines. One of Iowa greatest stopover points for every kind of migrating waterfowl, plus various species of loon, grebes pelicans and more.