Land for sale in Garfield County recently totaled almost $6 million and 1,000 acres. Garfield County ranks 36th out of 39 counties in the Evergreen State for the total number of acres of land currently advertised for sale. Pomeroy featured the most land for sale. From an economic perspective, government and state-level services contribute most to Garfield County's overall GDP. Garfield County is the 33rd biggest county (718 square miles) in Washington. It's located in the Eastern Washington region of the state.