The South Fork Umatilla River is a tributary of the
Umatilla River
The Umatilla River is an tributary of the Columbia River in northern Umatilla County, Oregon, United States. Draining a basin of , it enters the Columbia near the city of Umatilla in the northeastern part of the state. In downstream order, begi ...
in
Umatilla County
Umatilla County () is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 80,075. Hermiston is the largest city in Umatilla County, but Pendleton remains the county seat. Umatilla County is part of ...
in the
U.S. state
In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...
of
Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
.
Its headwaters lie in the
Umatilla National Forest
The Umatilla National Forest, in the Blue Mountains of northeast Oregon and southeast Washington, covers an area of 1.4 million acres (5,700 km2). In descending order of land area the forest is located in parts of Umatilla, Grant, Columbi ...
in the
Blue Mountains of northeastern Oregon near Pileup Saddle and Black Mountain. The South Fork flows generally north between Goodman Ridge and Bobsled Ridge to meet the
North Fork Umatilla River near Graves Butte. Together the forks form the
main stem
In hydrology, a mainstem (or trunk) is "the primary downstream segment of a river, as contrasted to its tributaries". Water enters the mainstem from the river's drainage basin, the land area through which the mainstem and its tributaries flow.. A ...
Umatilla.
Named tributaries of the South Fork from source to mouth are Shimmiehorn, Thomas, and Buck creeks, which all enter from the right. The North Fork also enters from the right.
The Umatilla Forks Campground and Day Use Area lies near the confluence of the forks. Open from June through September, it has campsites, picnic tables, toilets, drinking water, and parking spaces.
Forest Road 32 runs along the lower river below the mouth of Thomas Creek.
See also
*
List of rivers of Oregon
This is a partial listing of rivers in the state of Oregon, United States. This list of Oregon rivers is organized alphabetically and by tributary structure. The list may also include streams known as creeks, brooks, forks, branches and prongs, a ...
References
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Rivers of Oregon
Rivers of Umatilla County, Oregon