The North Fork Alsea River is a 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.