High Quality Content by WIKIPEDIA articles! The Willamette Valley (pronounced /w læm t/ wi-LAM-it) is the region in northwest Oregon in the United States that surrounds the Willamette River as it proceeds northward from its emergence from mountains near Eugene to its confluence with the Columbia River at Portland. A Small part of the Willamette Valley ecoregion is in southwestern Washington, around the city of Vancouver. BEing a productive agricultural area, the valley was the destination of choice for the emigrants on the Oregon Trail in the 1840s. IT has formed the cultural and political heart of Oregon since the days of the Oregon Territory, and is home to 70% of Oregon's population.