Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Pop. | 2020 Pop. | Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Arnold | 1 | 21,127 | 20,853 | 0.32% | 1,833 | 11.5 | City |
| Festus | 2 | 13,683 | 12,721 | 1.79% | 2,317 | 5.9 | City |
| Murphy | 3 | 8,383 | 8,373 | -0.26% | 2,170 | 3.9 | CDP |
| De Soto | 4 | 6,509 | 6,445 | 0.25% | 1,485 | 4.4 | City |
| Barnhart | 5 | 6,100 | 6,676 | 0.49% | 1,231 | 5.0 | CDP |
| Pevely | 6 | 6,068 | 6,050 | 0.07% | 1,200 | 5.1 | City |
| Imperial | 7 | 5,498 | 4,947 | 1.05% | 1,049 | 5.2 | CDP |
| Herculaneum | 8 | 5,422 | 4,713 | 3.38% | 1,304 | 4.2 | City |
| Crystal City | 9 | 4,711 | 4,734 | -0.13% | 1,043 | 4.5 | City |
| High Ridge | 10 | 4,709 | 4,257 | 0.62% | 1,249 | 3.8 | CDP |
| Hillsboro | 11 | 3,505 | 3,491 | 0.09% | 912 | 3.8 | City |
| Byrnes Mill | 12 | 3,188 | 3,176 | 0.09% | 620 | 5.1 | City |
| Terre Lac | 13 | 2,850 | 2,382 | 7.67% | 408 | 7.0 | CDP |
| Raintree Plantation | 14 | 2,135 | 1,980 | 7.72% | 1,093 | 2.0 | CDP |
| Cedar Hill | 15 | 1,408 | 1,625 | -1.61% | 614 | 2.3 | CDP |
| Summer Set | 16 | 1,363 | 1,030 | 7.75% | 1,495 | 0.9 | CDP |
| Horine | 17 | 966 | 1,090 | 1.15% | 1,357 | 0.7 | CDP |
| Lake Timberline | 18 | 746 | 548 | 7.8% | 314 | 2.4 | CDP |
| Olympian Village | 19 | 713 | 719 | -0.28% | 1,369 | 0.5 | City |
| Briarwood Estates | 20 | 326 | 255 | 7.95% | 479 | 0.7 | CDP |
| Cedar Hill Lakes | 21 | 200 | 204 | -0.5% | 922 | 0.2 | Village |
| Scotsdale | 22 | 198 | 193 | 0.51% | 341 | 0.6 | Town |
| Parkdale | 23 | 154 | 156 | -0.65% | 1,203 | 0.1 | Village |
| Kimmswick | 24 | 134 | 136 | -0.74% | 573 | 0.2 | City |
| Peaceful Village | 25 | 97 | 95 | 0% | 495 | 0.2 | Village |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Arnold is the largest city in Jefferson County.
Peaceful Village is the smallest city in Jefferson County.
There are 25 cities in Jefferson County, Missouri.