Alsea is an unincorporated community in Benton County, Oregon, United States. It is located on Oregon Route 34 and the Alsea River. Alsea was named for the Alsea River, whose name was a corruption of "Alsi" (also spelled "Ulseah" and "Alsiias") the name of a Native American tribe, now known as the Alsea, that lived at the mouth of the river. The Alsea area was settled by Europeans early as 1855, when the name "Alseya Settlement" appeared on the Surveyor General's map. Alsea post office was established in 1871. In the early 1850s settlers moved from the Willamette Valley into the Alsea area to take up donation land claims. While logging was once the primary industry in Alsea, it is now known as a place for fishing on Alsea River, particularly for steelhead. Alsea is home to the Hayden Bridge, a historic covered bridge listed on the National Register of Historic Places in 1979.