Washington County is in Southwestern Idaho. Of the 44 counties in the state, 1,473-square-mile Washington County ranks 20th by size. Idaho's Washington County includes nearly 4,000 acres of residential land and property for sale based on recent Land Network data. The combined market value of ranches, farms, hunting land and other rural land and acreage for sale here was nearly $37 million. The average price of residential acreage for sale in Washington County was $1 million. Browse all residential land and rural property for sale in Idaho 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.