Willamette River

The Willamette River is a major tributary of the Columbia River, accounting for 12 to 15 percent of the Columbia's flow. The Willamette's main stem is 187 miles (301 km) long, lying entirely in northwestern Oregon in the United States. Flowing northward between the Oregon Coast Range and the Cascade Range, the river and its tributaries form the Willamette Valley, a basin that contains two-thirds of Oregon's population, including the state capital, Salem, and the state's largest city, Portland, which surrounds the Willamette's mouth at the Columbia.

Willamette River
Mouth	Columbia River
Length	187 mi (301 km)
Mouth elevation	10 ft (3.0 m)

Originally created by plate tectonics about 35 million years ago and subsequently altered by volcanism and erosion, the river's drainage basin was significantly modified by the Missoula Floods at the end of the most recent ice age. Humans began living in the watershed over 10,000 years ago. There were once many tribal villages along the lower river and in the area around its mouth on the Columbia. Indigenous peoples lived throughout the upper reaches of the basin as well.

Willamette River Media

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  Ocean-going cargo ship anchored at the mouth of the Willamette

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  The Multnomah Channel from the Sauvie Island Bridge

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  The Oregon Route 34 bridge across the Willamette River at Corvallis is a mid-valley highway crossing.

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  The glacial Bellevue Erratic at Erratic Rock State Natural Site. The rock was transported to the Willamette Valley by the Missoula Floods.

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  Willamette Valley map showing main stem and major tributaries

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  The Willamette River near the confluence with the Molalla River

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  A boulder at Alton Baker Park in Eugene engraved with the Kalapuyan "Whilamut" "Where the river ripples and runs fast"

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  Oregon City circa 1867, with Willamette Falls in the background

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  Conveyor belt loading debris onto a barge as part of the Big Pipe Project

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  The weir-type dam at Willamette Falls

Works cited

• Bright, William (2004). Native American Placenames of the United States. Norman, Oklahoma: University of Oklahoma Press. ISBN 978-0-8061-3576-2. OCLC 53019644.