Land for sale in Douglas County, Illinois, recently totaled around $8 million and 1,000 acres. Douglas County ranks 58th out of 102 counties in the Inland Empire for the combined amount of land currently advertised for sale. Camargo had the most land for sale. From an economic perspective, manufacturing and related services are the main sectors in Douglas County. Douglas County is the 72nd biggest county (417 square miles) in Illinois. It's located in the Central Illinois region of the state.