A combined 1,000 acres were listed for sale in Washington's San Juan County recently; the value of all San Juan County land and rural real estate for sale was approximately $50 million. San Juan County ranks 36th out of 39 counties in the state for the total acreage of land currently advertised for sale. Friday Harbor featured the most land for sale. Based on its natural assets, tourism and recreation are important sectors for the San Juan County economy. San Juan County is the 36th biggest county (620 square miles) in Washington. It's located in the Puget Sound Washington region of Washington.