9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Polk township | 1 | 14,261 | 14,031 | 0.88% | 119 | 120.32 | Township |
| Bolivar | 2 | 11,695 | 10,802 | 1.55% | 1,421 | 8.23 | City |
| Humansville | 3 | 947 | 914 | 0.74% | 759 | 1.25 | City |
| Polk township | 4 | 711 | 731 | -1.11% | 13 | 56.51 | Township |
| Fair Play | 5 | 460 | 435 | 1.1% | 1,077 | 0.43 | City |
| Morrisville | 6 | 404 | 384 | 1% | 625 | 0.65 | Town |
| Halfway | 7 | 155 | 149 | 0.65% | 77 | 2.01 | Village |
| Flemington | 8 | 116 | 110 | 0.87% | 350 | 0.33 | Village |
| Aldrich | 9 | 70 | 67 | 1.45% | 490 | 0.14 | Village |
Polk township is the largest city in Polk County, with a population of 14,261.
Aldrich is the smallest city in Polk County.
There are 9 cities in Polk County, Missouri.