Description of Willamette River

The Willamette rises in three separate forks in the mountains south and southeast of Eugene, at the southern termination of the Willamette Valley. The Middle Fork and North Fork increase on the western side of the Cascades between Three Sisters south to Diamond Peak, with the Middle Fork in receipt of the North Fork northwest of Oakridge and flowing northwest through the mountains to the southern end of the Willamette Valley. The Coast Fork rises in the lower mountains south of Cottage Grove, sinuous north to connect the Middle Fork 2 mi southeast of Eugene.

From Eugene, the joint river flow NNW across the plain of the southern Willamette Valley to Corvallis, and then follows a zigzag course past Albany and around the isolated hills in the middle valley, passing west of downtown Salem. From Salem it flows north in a not direct course across the northwest plain of the valley, reaching the hills at Newberg, where it turns sharply ENE along the hills, passing through an opening in the hills at Oregon City, the location of the Falls of the Willamette and the head of navigation. From Oregon City it flows northwest, past Lake Oswego and Milwaukee on the south edge of Portland, then passing between east and west Portland, where it is spanned by a series of urban bridges. Downstream of downtown Portland it flows northwest through the industrial port area of Portland Harbor, then splitting into two channels around Sauvie Island, both of which hook around to enter the Columbia from the west, with the main channel entering on the north edge of Portland and the smaller Multnomah Channel entering approximately 15 mi NNW at St.Helens.