The South Branch Kishwaukee River originates on the Cropsey Moraine just north of Shabbona and flows northeasterly to the village of Genoa in DeKalb County before turning northwest through Ogle County and continuing into Winnebago County, where it joins the North Branch near Cherry Valley. This tributary of the main Kishwaukee River has an average width of 55 feet and cuts across moraines, with portions of the riverbed following the plain of an ancient lake. The river features a mix of gravel and bedrock-laden bottoms, creating excellent habitat diversity with riffles, pools, and runs throughout its length. The South Branch flows through both rural agricultural areas and urban sections, offering scenic stream bank fishing opportunities across its three-county span.