The Willamette Valley is a long valley in the Pacific Northwest region of the United States, located entirely within the state of Oregon. The valley forms the cultural and political heart of Oregon and is home to approximately 70 percent 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, which is surrounded by mountains on three sides - the Oregon Coast Range to the west, the Cascade Range to the east, and the Calapooya Mountains to the south.