Adams County is in Western Illinois. Of the 102 counties in the Prairie State, 871-square-mile Adams County ranks 12th by size. A recent survey of Land Network data includes 1,000 acres of residential land for sale in Illinois's Adams County, which is valued at a combined $13 million. The average price of residential acreage for sale in Adams County was $377,491. 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.