About the Basin

ValleyThe Lower Wisconsin River Basin encompasses the land draining to that portion of the Wisconsin River from Wisconsin Dells to its mouth at Prairie du Chien. Rich in natural and human history, the Basin is the subject of a great body of literature.

The Basin’s natural boundaries include the Military Ridge to the south, the sand plain of glacial Lake Wisconsin to the northeast, the unglaciated hills and valleys to the west and southwest and the rolling, glaciated hills of the Fox and Rock River drainages to the east.

Evidence of glaciation abounds in the Basin, even though glaciers only covered a small fraction of the land area. The river valley itself is comprised of complex terraces and wetlands formed by movement of the river itself through deep sand and gravel, sometimes hundreds of feet thick, formed by outwash from the drainage of glacial lake Wisconsin. The entire western and southern portions of the basin are part of Wisconsin’s Driftless Area, that portion of the state (and parts of southeast Minnesota, northeast Iowa and northwest Illinois). Excellent discussion and illustrations of the formation of these, and other geologic features of the basin can be found in Robert Dott and John Attig’s Roadside Geology of Wisconsin.

The natural and recreational heart of the Basin is the Lower Wisconsin State Riverway (LWR), a 92-mile stretched of un-dammed and spectacularly beautiful river valley winding southwest from Prairie du Sac to Prairie du Chien. In response to a number of proposals during the 1980s, citizens debated, sometimes acrimoniously, how to compromise the need to protect and conserve a unique natural resource with the rights and responsibilities of private landowners. The resulting LWR is considered by many to be a model in balancing those interests.

Lower Wisconsin Basin Map


Roadside Geology of Wisconsin
Lower Wisconsin State Riverway Board