| Zip Code | City | Population ↓ |
|---|---|---|
| 98632 | Longview | 50,837 |
| 98626 | Kelso | 27,000 |
| 98674 | Woodland | 15,679 |
| 98611 | Castle Rock | 9,341 |
| 98625 | Kalama | 6,827 |
| 98645 | Silverlake | 2,044 |
| 98603 | Ariel | 1,192 |
| 98649 | Toutle | 849 |
| 98581 | Ryderwood | 425 |
| 98609 | Carrolls | 0 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 10 ZCTAs in Cowlitz County, Washington (US Census).