The Coast Fork Willamette River is one of several forks that unite to form the Willamette River

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 long, lying entirely in northwestern Oregon in the United States...

 in western Oregon

Oregon

Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

 in the United States. It is about 40 miles (64.4 km) long, draining an area of the mountains at the south end of the Willamette Valley

Willamette Valley

The Willamette Valley is the most populated region in the state of Oregon of the United States. Located in the state's northwest, the region is surrounded by tall mountain ranges to the east, west and south and the valley's floor is broad, flat and fertile because of Ice Age conditions...

 south of Eugene

Eugene, Oregon

Eugene is the second largest city in the U.S. state of Oregon and the seat of Lane County. It is located at the south end of the Willamette Valley, at the confluence of the McKenzie and Willamette rivers, about east of the Oregon Coast.As of the 2010 U.S...

.

Course

The Coast Fork Willamette River is formed in southwestern Lane County

Lane County, Oregon

-National protected areas:*Oregon Islands National Wildlife Refuge *Siuslaw National Forest *Umpqua National Forest *Willamette National Forest -Government:...

, in the Calapooya Mountains

Calapooya Mountains

The Calapooya Mountains are a mountain range in Lane and Douglas counties of southwestern Oregon in the United States. The range runs for approximately west from the Cascade Range between Eugene on the north and Roseburg on the south.- Geology :...

, by the confluence of Garoutte Creek and the Big River

Big River (Oregon)

The Big River is a tributary of the Coast Fork Willamette River, approximately 12 mi long, in western Oregon in the United States. It drains an area of the Calapooya Mountains south of Eugene....

. The river flows north through the mountains, through the Cottage Grove Lake reservoir, to Cottage Grove

Cottage Grove, Oregon

Cottage Grove is a city in Lane County, Oregon, United States. It received its name from its first postmaster, G. C. Pierce, in September 1861. Pierce's home at the time was in an oak grove. The population was 9,686 at the 2010 census.-History:...

, where it receives the Row River

Row River

The Row River is a river, approximately long, in Lane County, Oregon, United States. It rises in the Cascade Range and flows into the Coast Fork Willamette River near Cottage Grove. The stream was originally known as the "East Fork Coast Fork", but was later renamed after a dispute between...

 from the southeast. It continues north past Creswell

Creswell, Oregon

Creswell is a city in the Willamette Valley of Lane County, Oregon, United States. The population at the 2010 census was 5,031.- Geography :According to the United States Census Bureau, the city has a total area of , of which , or 2.42%, is water....

 and joins the Middle Fork

Middle Fork Willamette River

The Middle Fork Willamette River is one of several forks that unite to form the Willamette River in the western part of the U.S. state of Oregon...

from the south, about 2 miles (3.2 km) southwest of Eugene, to form the Willamette.