The Willamette Falls is a natural waterfall in the northwestern United States, located on the Willamette River between Oregon City and West Linn, Oregon. The largest waterfall in the Northwest U.S. by volume, it is the seventeenth widest in the world. Horseshoe in shape, it is 1,500 feet wide and forty feet high, with a flow rate of 30,850 cu ft/s. Located 2…The Willamette Falls is a natural waterfall in the northwestern United States, located on the Willamette River between Oregon City and West Linn, Oregon. The largest waterfall in the Northwest U.S. by volume, it is the seventeenth widest in the world. Horseshoe in shape, it is 1,500 feet wide and forty feet high, with a flow rate of 30,850 cu ft/s. Located 26 miles upriver from the Willamette's mouth at Portland, Willamette Falls is a culturally significant site for many tribal communities in the region.