18 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Des Moines | 1 | 208,084 | 213,826 | -0.55% | 2,360 | 88.16 | City |
| Ankeny | 2 | 78,412 | 68,527 | 2.59% | 2,474 | 31.69 | City |
| West Des Moines | 3 | 74,395 | 68,919 | 1.49% | 1,573 | 47.29 | City |
| Urbandale | 4 | 47,495 | 45,579 | 0.81% | 2,106 | 22.55 | City |
| Johnston | 5 | 24,992 | 24,111 | 0.71% | 1,282 | 19.49 | City |
| Altoona | 6 | 23,047 | 19,674 | 3.02% | 1,942 | 11.87 | City |
| Clive | 7 | 19,239 | 18,654 | 0.61% | 2,514 | 7.65 | City |
| Grimes | 8 | 16,869 | 15,601 | 1.53% | 1,405 | 12.01 | City |
| Pleasant Hill | 9 | 12,567 | 10,192 | 3.93% | 1,162 | 10.81 | City |
| Bondurant | 10 | 9,972 | 7,439 | 5.36% | 1,052 | 9.48 | City |
| Polk City | 11 | 6,772 | 5,599 | 3.59% | 1,202 | 5.64 | City |
| Windsor Heights | 12 | 4,952 | 5,239 | -1.14% | 3,453 | 1.43 | City |
| Saylorville | 13 | 2,721 | 2,743 | -1.41% | 401 | 6.79 | CDP |
| Mitchellville | 14 | 2,705 | 2,485 | 1.65% | 1,073 | 2.52 | City |
| Elkhart | 15 | 1,140 | 892 | 4.59% | 604 | 1.89 | City |
| Runnells | 16 | 448 | 455 | -0.22% | 1,082 | 0.41 | City |
| Alleman | 17 | 434 | 433 | 0% | 148 | 2.94 | City |
| Sheldahl | 18 | 319 | 299 | 1.27% | 395 | 0.81 | City |
Des Moines is the largest city in Polk County, with a population of 208,084.
Sheldahl is the smallest city in Polk County.
There are 18 cities in Polk County, Iowa.