A total of around 1,000 acres were listed for sale in Whiteside County, Illinois, recently; the combined value of all Whiteside County farms, rural land, hunting land and other land for sale was nearly $25 million. Whiteside County ranks 26th out of 102 counties in the Prairie State for the total number of acres of land currently advertised for sale. Sterling featured the most land for sale. Manufacturing and related services are the largest economic sectors in Whiteside County. Whiteside County is Illinois's 27th largest county (696 square miles). It's located in the Northern Illinois region of the state.