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. The value of all land and rural real estate for sale in Washington County, Oregon, recently was $151 million, representing a total of 3,750 acres of land for sale in Washington County. Washington County ranks 17th in the state for the total number of acres of land currently advertised for sale. Of all farms and ranches for sale in Washington County, Hillsboro had 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.