| Locality | Post Code |
|---|---|
| Ariel, Cowlitz | 98603 |
| Carrolls, Cowlitz | 98609 |
| Castle Rock, Cowlitz | 98611 |
| Cougar, Cowlitz | 98616 |
| Kalama, Cowlitz | 98625 |
| Kelso, Cowlitz | 98626 |
| Longview, Cowlitz | 98632 |
| Ryderwood, Cowlitz | 98581 |
| Silverlake, Cowlitz | 98645 |
| Toutle, Cowlitz | 98649 |
| Woodland, Cowlitz | 98674 |
| Yale, Cowlitz | 98603 |