9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Puget Island | 1 | 1,113 | 1,227 | 1.64% | 147 | 7.57 | CDP |
| East Cathlamet | 2 | 652 | 512 | 1.56% | 381 | 1.71 | CDP |
| Cathlamet | 3 | 616 | 561 | 1.82% | 1,217 | 0.51 | Town |
| Lower Elochoman | 4 | 510 | 475 | 4.51% | 338 | 1.51 | CDP |
| Rosburg | 5 | 457 | 320 | 2.01% | 20 | 22.91 | CDP |
| Skamokawa Valley | 6 | 260 | 268 | -3.35% | 9 | 28.20 | CDP |
| Grays River | 7 | 256 | 309 | 0% | 13 | 20.18 | CDP |
| Upper Elochoman | 8 | 85 | 119 | -8.6% | 59 | 1.45 | CDP |
| Altoona | 9 | 66 | 35 | 6.45% | 13 | 5.09 | CDP |
Puget Island is the largest city in Wahkiakum County, with a population of 1,113.
Altoona is the smallest city in Wahkiakum County.
There are 9 cities in Wahkiakum County, Washington.