14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Centralia | 1 | 19,077 | 18,269 | 0.86% | 2,503 | 7.62 | City |
| Chehalis | 2 | 7,632 | 7,479 | 0.41% | 1,314 | 5.81 | City |
| Grand Mound | 3 | 3,557 | 3,957 | 1.08% | 857 | 4.15 | CDP |
| Fords Prairie | 4 | 3,063 | 2,582 | 2.48% | 822 | 3.73 | CDP |
| Napavine | 5 | 2,302 | 1,897 | 3.65% | 796 | 2.89 | City |
| Winlock | 6 | 2,252 | 1,482 | 7.34% | 1,743 | 1.29 | City |
| Morton | 7 | 1,121 | 1,038 | 1.54% | 1,365 | 0.82 | City |
| Toledo | 8 | 848 | 633 | 5.34% | 2,152 | 0.39 | City |
| Mossyrock | 9 | 808 | 770 | 1% | 1,174 | 0.69 | City |
| Vader | 10 | 716 | 631 | 2.43% | 771 | 0.93 | City |
| Pe Ell | 11 | 679 | 646 | 1.04% | 1,149 | 0.59 | Town |
| Onalaska | 12 | 593 | 431 | -0.34% | 370 | 1.60 | CDP |
| Packwood | 13 | 60 | 294 | -23.08% | 60 | 1 | CDP |
| Mineral | 14 | 36 | 135 | -23.4% | 54 | 0.67 | CDP |
Centralia is the largest city in Lewis County, with a population of 19,077.
Mineral is the smallest city in Lewis County.
There are 14 cities in Lewis County, Washington.