6 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Pasco | 1 | 81,605 | 77,687 | 0.97% | 2,094 | 38.96 | City |
| Connell | 2 | 4,261 | 5,445 | -5.27% | 573 | 7.44 | City |
| Basin City | 3 | 1,689 | 1,173 | 2.36% | 530 | 3.19 | CDP |
| West Pasco | 4 | 1,403 | 1,592 | -9.95% | 960 | 1.46 | CDP |
| Mesa | 5 | 383 | 387 | -0.26% | 231 | 1.66 | City |
| Kahlotus | 6 | 135 | 142 | -0.73% | 355 | 0.38 | City |
Pasco is the largest city in Franklin County, with a population of 81,605.
Kahlotus is the smallest city in Franklin County.
There are 6 cities in Franklin County, Washington.