Skamokawa Valley is a census-designated place (CDP) in Wahkiakum County, Washington, north of the town of Cathlamet. As of the 2020 census, Skamokawa Valley had a population of 487. The CDP includes the Sleepy Hollow community. The Skamokawa Valley community is part of the Wahkiakum School District, a K-12 school district of about 430 students. The unincorporated community of Skamokawa lies directly to the south.