Land for sale in Ohio's Washington County recently totaled nearly $28 million and almost 2,000 acres. Washington County ranks 39th in the state for the total acreage of land currently advertised for sale. There were two properties listed as sold in Washington County through the Land Network Comparable Sales Program. This represented a total value of $1,210,000. Marietta had the most land for sale. Washington County is one of the ten largest counties in Ohio (639 square miles). It's located in the Southeast Ohio region of Ohio.