Warren County is in Western Illinois. Of the 102 counties in the Prairie State, Warren County is 49th in terms of its size (543 square miles). There is about 1,000 acres of residential land for sale in Warren County, Illinois, based on recent Land Network data, making it the most common type of land for sale in Warren County. The combined market value of farms, hunting land and other rural land and acreage for sale here is $2 million. The average price of residential land for sale in Warren County was $218,100. 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.