McHenry County is in Northern Illinois. Of the 102 counties in the state, McHenry County ranks 36th in terms of size (611 square miles). McHenry County, Illinois, has almost 1,000 acres of residential land for sale based on recent Land Network data. The combined market value of farms, hunting land and other rural land and acreage for sale here was almost $100 million. The average price of residential land for sale in McHenry County was $867,926. 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.