Post Offices List in Wahkiakum County, Washington:
| Cathlamet Post Office | 30 River St, Cathlamet, WA 98612 |
| Skamokawa Post Office | 1391 W State Route 4, Skamokawa, WA 98647 |
| Rosburg Post Office | 4182 State Route 4 W, Rosburg, WA 98643 |
| Cathlamet Post Office | 30 River St, Cathlamet, WA 98612 |
| Skamokawa Post Office | 1391 W State Route 4, Skamokawa, WA 98647 |
| Rosburg Post Office | 4182 State Route 4 W, Rosburg, WA 98643 |