North Fork Alsea River

{{Use American English|date=February 2025}}

{{Infobox river

| name = North Fork Alsea River

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| name_etymology = Alsi, said to be a corruption of Alsea for native people who lived near the mouth of the river{{cite book | last = McArthur | first = Lewis A. |author2=McArthur, Lewis L. | title = Oregon Geographic Names|edition=7th | publisher = Oregon Historical Society Press | year = 2003 |origyear=1928| location = Portland, Oregon | pages = 19–20| isbn = 0-87595-277-1}}

| image = North Fork Alsea River at Clemens Park.JPG

| image_caption = The North Fork Alsea River at Clemens Park in Benton County

| image_size = 300

| map =

| map_size = 300

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| pushpin_map = USA Oregon

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| pushpin_map_caption= Location of the mouth of North Fork Alsea River in Oregon

| subdivision_type1 = Country

| subdivision_name1 = United States

| subdivision_type2 = State

| subdivision_name2 = Oregon

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| subdivision_type4 = County

| subdivision_name4 = Lincoln and Benton

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| length = {{convert|16|mi|km|abbr=on}}

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| source1 = Klickitat Lake

| source1_location = Central Oregon Coast Range, Lincoln County

| source1_coordinates= {{coord|44|28|40|N|123|39|26|W|display=inline}}{{cite web|title = North Fork Alsea River| work = Geographic Names Information System |url = {{gnis3|1146901}}|publisher = United States Geological Survey (USGS)|date = November 28, 1980|accessdate = November 16, 2015}}

| source1_elevation = {{convert|1171|ft|abbr=on}}Source elevation derived from Google Earth search using GNIS source coordinates.

| mouth = Alsea River

| mouth_location = near Alsea, Benton County

| mouth_coordinates = {{coord|44|22|34|N|123|36|10|W|display=inline,title}}

| mouth_elevation = {{convert|272|ft|abbr=on}}

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The North Fork Alsea River is a {{convert|16|mi|km|adj=on}} tributary of the Alsea River in the U.S. state of Oregon. It begins at Klickitat Lake, fed by Klickitat and Lake creeks in the Central Oregon Coast Range, and flows generally south to near Alsea, where it joins the South Fork Alsea River to form the main stem. For most of its course, the North Fork winds through the Siuslaw National Forest in Lincoln County and then Benton County. It passes under Oregon Route 34 northeast of Alsea.{{cite web|title=United States Topographic Map|url=http://mapper.acme.com/?ll=44.376111,-123.602778&z=12&t=T&marker0=44.376111,-123.602778,User%3AFinetooth%2FSandbox6|via=|accessdate=November 16, 2015}} The map includes markers at {{convert|1|mi|km|adj=on}} intervals along the course.

The Alsea Hatchery, constructed by the state in 1936, raises winter steelhead and other rainbow trout along the North Fork.{{cite web|title=Alsea Hatchery|publisher=Oregon Department of Fish and Wildlife|url=http://www.dfw.state.or.us/resources/visitors/alsea_hatchery.asp|year=2015|accessdate=November 16, 2015}} According to Fishing in Oregon, the river is a "beautiful stream (well-suited to fly angling) with a large run of hatchery winter steelhead."{{cite book|last=Sheehan|first=Madelynne Diness|title=Fishing in Oregon: The Complete Oregon Fishing Guide|edition=10th|publisher=Flying Pencil Publications|location=Scappoose, Oregon|page=7|isbn=0-916473-15-5}} The stream also supports populations of wild cutthroat trout. It is closed to salmon fishing or fishing from a floating device.

Clemens Park, a Benton County park of about {{convert|38|acre|ha}}, lies along the North Fork and Route 34 near Alsea. Amenities include picnic tables, restrooms, a self-guided nature trail, fishing and "areas for water play".{{cite web|title=Clemens Park|url=https://www.co.benton.or.us/parks/page/clemens-park|publisher=Benton County|accessdate=November 16, 2015}}