| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Dallas | 1 | 18,097 | 17,002 | 1.16% | 3,685 | 5 | City |
| Monmouth | 2 | 11,666 | 11,145 | 1.07% | 5,210 | 2 | City |
| Independence | 3 | 10,258 | 9,997 | 0.62% | 3,427 | 3 | City |
| Falls City | 4 | 1,041 | 1,055 | -0.1% | 866 | 1 | City |
Dallas is the largest city in Polk County, with a population of 18,097.
Falls City is the smallest city in Polk County, with a population of 1,041.
There are 4 cities in Polk County, Oregon.