18 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Des Moines | 1 | 212,927 | 213,769 | -0.08% | 2,415 | 88 | City |
| Ankeny | 2 | 78,768 | 68,562 | 2.66% | 2,485 | 32 | City |
| West Des Moines | 3 | 74,850 | 68,920 | 1.61% | 1,583 | 47 | City |
| Urbandale | 4 | 48,304 | 45,577 | 1.14% | 2,142 | 23 | City |
| Johnston | 5 | 25,279 | 23,992 | 1.03% | 1,297 | 19 | City |
| Altoona | 6 | 23,309 | 19,751 | 3.15% | 1,964 | 12 | City |
| Clive | 7 | 19,717 | 18,672 | 1.07% | 2,576 | 8 | City |
| Grimes | 8 | 17,653 | 15,718 | 2.24% | 1,470 | 12 | City |
| Pleasant Hill | 9 | 12,386 | 10,165 | 3.72% | 1,145 | 11 | City |
| Bondurant | 10 | 10,022 | 7,467 | 5.37% | 1,058 | 9 | City |
| Polk City | 11 | 6,637 | 5,599 | 3.22% | 1,178 | 6 | City |
| Windsor Heights | 12 | 5,073 | 5,236 | -0.65% | 3,538 | 1 | City |
| Mitchellville | 13 | 2,735 | 2,487 | 1.82% | 1,084 | 3 | City |
| Saylorville | 14 | 2,721 | 2,743 | -1.41% | 401 | 7 | CDP |
| Elkhart | 15 | 1,126 | 891 | 4.36% | 597 | 2 | City |
| Runnells | 16 | 468 | 462 | 0.21% | 1,130 | 0 | City |
| Alleman | 17 | 440 | 432 | 0.23% | 150 | 3 | City |
| Sheldahl | 18 | 315 | 298 | 0.96% | 390 | 1 | City |
Des Moines is the largest city in Polk County, with a population of 212,927.
Sheldahl is the smallest city in Polk County, with a population of 315.
There are 18 cities in Polk County, Iowa.