The Willamette Valley (/wɨˈlæmɨt/) is a 150-mile long valley in the U.S. state of Oregon in the Pacific Northwest region of the United States. The valley forms the cultural and political heart of Oregon and is home to 70% of its population including Portland, its largest city, as well as Salem, the state capital. The Willamette River flows the entire length of the valley, depositing highly fertile alluvial-deposited soils across its broad, flat plain. The valley is surrounded by mountain ranges on three sides - the Oregon Coast Range to the west, the Cascade Range to the east, and the Calapooya Mountains to the south.