9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Polk | 1 | 13,740 | 14,041 | -0.67% | 114 | 120 | Township |
| Bolivar | 2 | 11,921 | 10,804 | 1.58% | 1,449 | 8 | City |
| Humansville | 3 | 952 | 913 | 0.74% | 763 | 1 | City |
| Polk | 4 | 720 | 730 | -0.28% | 13 | 57 | Township |
| Fair Play | 5 | 457 | 435 | 0.88% | 1,070 | 0 | City |
| Morrisville | 6 | 404 | 385 | 0.75% | 625 | 1 | Town |
| Halfway | 7 | 155 | 148 | 0.65% | 77 | 2 | Village |
| Flemington | 8 | 115 | 111 | 0.88% | 347 | 0 | Village |
| Aldrich | 9 | 70 | 66 | 1.45% | 490 | 0 | Village |
Polk is the largest city in Polk County, with a population of 13,740.
Aldrich is the smallest city in Polk County, with a population of 70.
There are 9 cities in Polk County, Missouri.