Rock Island County is in Western Illinois. Of the 102 counties in the Prairie State, Rock Island County ranks 62nd in terms of size (288,824 acres). The total value of about 1,000 acres of residential land recently listed for sale in Rock Island County, Illinois, was approximately $7 million. The average price of residential land for sale in Rock Island County was $378,672. Browse all residential land and rural property for sale in Illinois to find residential land and properties that suit your lifestyle needs, from existing residential homes and estates to land ready for future residential-property development.