Rosburg is a Census-designated place (CDP) in Wahkiakum County, Washington, United States. Rosburg is located on the Grays River near Washington State Route 4, 15 miles (24 km) northwest of Cathlamet. Rosburg has a post office with ZIP code 98643. The CDP includes the communities of Eden and Oneida.
Christian Rosburg, the town's first postmaster, named Rosburg for himself.