Kidd Lake State Natural Area is a protected area of Illinois on 800 acres (324 ha) in Monroe County, Illinois, United States, adjacent to the Fults Hill Prairie State Natural Area. Kidd Lake State Natural Area is an example of the once expansive wetlands of the Mississippi floodplain known as the American Bottoms. The marsh was historically part of an 800-acre (324 ha) lake bed, and was once home to a variety of wetland birds, some now rare in Illinois. It is an important rest stop for migrating waterfowl and continues to provide critical habitat to a diverse range of birds, as well as amphibians and reptiles.