The Willamette Valley () is a long valley in the Pacific Northwest region of the United States. The entire valley is in the state of Oregon. The valley contains the political and cultural areas of Oregon. It is home to about 70 percent of its population. This includes Portland, its largest city, and Salem, the state capital. The Willamette River flows the entire length of the valley. The valley 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.