9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Centralia | 1 | 19,393 | 18,397 | 0.86% | 2,483 | 8 | City |
| Chehalis | 2 | 7,836 | 7,479 | 0.77% | 1,349 | 6 | City |
| Winlock | 3 | 2,855 | 1,834 | 6.33% | 844 | 3 | City |
| Napavine | 4 | 2,280 | 1,905 | 2.84% | 788 | 3 | City |
| Morton | 5 | 1,113 | 1,040 | 1.09% | 1,356 | 1 | City |
| Toledo | 6 | 832 | 636 | 4.13% | 1,247 | 1 | City |
| Mossyrock | 7 | 818 | 773 | 0.99% | 1,189 | 1 | City |
| Vader | 8 | 725 | 620 | 2.55% | 780 | 1 | City |
| Pe Ell | 9 | 682 | 648 | 0.89% | 1,154 | 1 | Town |
Centralia is the largest city in Lewis County, with a population of 19,393.
Pe Ell is the smallest city in Lewis County, with a population of 682.
There are 9 cities in Lewis County, Washington.