Washington County is part of the the Chehalem Mountains AVA wine region, which sits on a series of sedimentary ridges that provide diverse soils and growing conditions at slightly higher altitudes than other Willamette Valley vineyards. Some 150 vineyards are located throughout the hilly countryside, comprising three counties—Yamhill, Washington and Clackamas—which frame the southwestern suburbs of the Portland metropolitan area. Land for sale in Washington County recently totaled approximately $160 million and nearly 4,000 acres. Washington County ranks 18th out of 36 counties in the Beaver State for the total acreage of land currently advertised for sale. Hillsboro featured the most land for sale. From an economic perspective, manufacturing and related services are the main sectors in Washington County. Washington County is the 31st biggest county (726 square miles) in Oregon. It's located in the Portland Metro Oregon region of Oregon.