2018 Map of Clear Lake

About this map

The Illinois River and Sangamon River converge in this complex riverine landscape, creating a maze of sloughs, lakes, and low-lying islands along the borders of Schuyler, Cass, and Mason counties. This hydrologic junction defines the area, with the larger Illinois River flowing past Elm Island while the Sangamon River meanders toward its mouth, feeding into a series of large backwater bodies like Clear Lake, Otter Lake, and Crane Lake. The map reveals how the seasonal rise and fall of these rivers has shaped the local geography, leaving behind features such as Eagle Slough, Ash Swale, and Redhead Lake.