There was a combined approximately $25 million of land for sale in Oregon's Gilliam County recently on Land.com. The total of all Gilliam County farms and ranches for sale was almost 100,000 acres. Gilliam County ranks 36th out of 36 counties in the Union State for the combined amount of land currently advertised for sale. Of all locations in Gilliam County with land for sale, Arlington had the most land for sale. Gilliam County is the 25th largest county (1,222 square miles) in Oregon. It's located in the Central Oregon region of the state.