Rock River

State: Illinois, Wisconsin

Lat/Long: 41.4825, -90.6162

Originating in southeastern Wisconsin, the three-hundred-mile-long Rock River flows roughly southwest, passing through Beloit and Rockford before flowing into the Mississippi River at Rock Island.

John M. Peck, A Gazetteer of Illinois in Three Parts (Jacksonville, IL: R. Goudy, 1834), 321; U.S. Geological Survey Geographic Names Information System: Rock River, accessed June 7, 2018, https://geonames.usgs.gov/apex/f?p=gnispq:3:::NO::P3_FID:416824.