{{Use American English|date=February 2025}} {{Infobox river | name = Coos River | name_native = | name_native_lang = | name_other = | name_etymology = Indian name for a native tribe living near Coos Bay<ref name = "McArthur">McArthur, p. 228</ref> <!---------------------- IMAGE & MAP --> | image = Coos river.jpg | image_caption = Coos River at the Chandler Bridge | image_size = 300 | map = | map_size = 300 | map_caption = | pushpin_map = USA Oregon | pushpin_map_size = 300 | pushpin_map_caption= Location of the mouth of the Coos River in Oregon <!---------------------- LOCATION --> | subdivision_type1 = Country | subdivision_name1 = United States | subdivision_type2 = State | subdivision_name2 = Oregon | subdivision_type3 = | subdivision_name3 = | subdivision_type4 = County | subdivision_name4 = Coos | subdivision_type5 = | subdivision_name5 = <!---------------------- PHYSICAL CHARACTERISTICS --> | length = {{convert|5|mi|km|abbr=on}}<ref name="topoquest Coos">{{cite web | author = United States Geological Survey |title = United States Geological Survey Topographic Map| publisher = TopoQuest | url =http://www.topoquest.com/map.php?lat=43.37718&lon=-124.10663&datum=nad83&zoom=4&map=auto&coord=d&mode=zoomin&size=m|accessdate = April 1, 2011}} The Allegany quadrangle of the map includes river mile (RM) markers for the river's entire length.</ref> | width_min = | width_avg = | width_max = | depth_min = | depth_avg = | depth_max = | discharge1_location= | discharge1_min = | discharge1_avg = {{convert|1441|cuft/s|m3/s|abbr=on}}<ref name="Palmer">{{cite book|author=Palmer, Tim|title=Field Guide to Oregon Rivers|publisher=Oregon State University Press|location=Corvallis|year=2014|pages=106–08|isbn=978-0-87071-627-0}}</ref> | discharge1_max = <!---------------------- BASIN FEATURES --> | source1 = Confluence of Millicoma River and South Fork Coos River | source1_location = Coos County, Oregon | source1_coordinates= {{coord|43|22|39|N|124|05|57|W|display=inline}}<ref name="gnis"/> | source1_elevation = {{convert|13|ft|abbr=on}}<ref name="gnis south fork mouth">{{cite gnis|id=1127273|name=South Fork Coos River|accessdate=2008-11-13}}</ref> | mouth = Coos Bay | mouth_location = Coos Bay, Coos County, Oregon | mouth_coordinates = {{coord|43|21|45|N|124|10|25|W|display=inline,title}}<ref name="gnis">{{cite web | work = Geographic Names Information System| publisher = United States Geological Survey | date = November 28, 1980 | url ={{Gnis3|1140087}}| title = Coos River | accessdate = April 1, 2011}}</ref> | mouth_elevation = {{convert|0|ft|abbr=on}}<ref name="gnis"/> | progression = | river_system = | basin_size = {{convert|730|sqmi|abbr=on}}<ref name = "fish plan"/> | tributaries_left = | tributaries_right = | custom_label = | custom_data = | extra = }}

The '''Coos River''' flows for about {{convert|5|mi|km}} into Coos Bay along the Pacific coast of southwest Oregon in the United States.<ref name="topoquest Coos"/> Formed by the confluence of its major tributaries, the South Fork Coos River and the Millicoma River, it drains an important timber-producing region of the Southern Oregon Coast Range.<ref name = "fish plan">{{cite web| author = Oregon Department of Fish and Wildlife|author2=Citizen Advisory Committee| title = Coos River Basin Fish Management Plan|url= https://scholarsbank.uoregon.edu/xmlui/bitstream/handle/1794/6771/coos%20river%20basin.pdf?sequence=1|publisher = University of Oregon|format=PDF|year = 1990|page=7|accessdate=April 1, 2011}}</ref> The course of the main stem and the major tributaries is generally westward from the coastal forests to the eastern end of Coos Bay near the city of Coos Bay.<ref name="DeLorme">{{cite map |publisher = DeLorme Mapping |title = Oregon Atlas and Gazetteer |edition = 1991 |section =33&ndash;34 |isbn = 978-0-89933-347-2}}</ref>

The river is the largest tributary of Coos Bay, which at about {{convert|10000|acre|ha}} is the largest estuary that lies entirely within Oregon.<ref name ="fish plan"/> The river enters the bay about {{convert|15|mi|km}}<ref name ="fish plan"/> from where the bay&mdash;curving east, north, and west of the cities of Coos Bay and North Bend and passing by the communities of Barview and Charleston&mdash;meets the ocean.<ref name="DeLorme"/> About 30 other tributaries also enter the bay directly.<ref name ="fish plan"/>

Most of the Coos River watershed of {{convert|730|mi2|km2}} is in Coos County, but {{convert|147|mi2|km2}} are in eastern Douglas County.<ref name = "fish plan"/> Commercial forests cover about 85&nbsp;percent of the basin.<ref name = "fish plan"/>

The river supports populations of chinook and coho salmon, Pacific lamprey,<ref name=":0">Larsen, Erik. Lamprey in the Coos Estuary. Partnership for Coastal Watersheds, 23 Apr. 2014, www.partnershipforcoastalwatersheds.org/wordpress/wp-content/uploads/2015/10/FINAL-Lamprey-Data-Summary-03122014.pdf. Pamphlet. </ref> western brook lamprey,<ref name=":0" /> shad, steelhead, and coastal cutthroat trout. Since public river-bank access is limited, fishing is often done by boat.<ref name = "Sheehan">Sheehan, pp. 66&ndash;67</ref>

==Course== Flowing west from the confluence of the South Fork Coos River and the Millicoma River, the Coos River is bordered by Oregon Route 241 (Coos River Highway) on the right and Coos River Road on the left. Downstream from its source, the river receives Noah Creek from the right {{convert|4|mi|km}} from the river mouth. Curving south, the river receives Vogel Creek and then Lillian Creek, both from the left, before passing under Chandler Bridge, which carries Route 241 from the right bank to the left bank about {{convert|2|mi|km|0}} from the mouth. The river then turns west and north as it enters the bay and splits into two distributaries separated by a marsh. The Cooston Channel, which is on the right, continues north around the west side of the marsh for about {{convert|1|mi|km}} to the mouth. The left-hand channel almost immediately merges with Catching Slough, which enters from the left and continues around the east side of the marsh to meet the Marshfield Channel of the bay.<ref name="topoquest Coos"/><ref name="DeLorme"/>

===Discharge=== Estimates of the average discharge of the Coos River varies from {{convert|90|cuft/s|m3/s}} in late summer to {{convert|5500|cuft/s|m3/s}} in February. Estimated extremes vary from a low of {{convert|50|cuft/s|m3/s}} to a high of {{convert|100000|cuft/s|m3/s}}.<ref name = "fish plan"/>

==See also== *List of rivers of Oregon

==References== {{reflist|2}}

==Works cited== *McArthur, Lewis A., and McArthur, Lewis L. (2003) [1928]. ''Oregon Geographic Names'', 7th ed. Portland: Oregon Historical Society Press. {{ISBN|0-87595-277-1}}. *Sheehan, Madelynne Diness (2005). ''Fishing in Oregon: The Complete Oregon Fishing Guide'', 10th ed. Scappoose, Oregon: Flying Pencil Publications. {{ISBN|0-916473-15-5}}. *Larsen, Erik. Lamprey in the Coos Estuary. Partnership for Coastal Watersheds, 23 Apr. 2014, [http://www.partnershipforcoastalwatersheds.org/wordpress/wp-content/uploads/2015/10/FINAL-Lamprey-Data-Summary-03122014.pdf www.partnershipforcoastalwatersheds.org/wordpress/wp-content/uploads/2015/10/FINAL-Lamprey-Data-Summary-03122014.pdf]. Pamphlet.

==External links== *[https://web.archive.org/web/20110430233048/http://www.cooswatershed.org/home.html Coos Watershed Association] *[http://www.partnershipforcoastalwatersheds.org/wordpress/wp-content/uploads/2015/10/FINAL-Lamprey-Data-Summary-03122014.pdf Lamprey in the Coos Estuary]

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Category:Rivers of Oregon Category:Rivers of Douglas County, Oregon Category:Rivers of Coos County, Oregon Category:Oregon placenames of Native American origin