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 |
|---|---|---|---|---|---|---|---|
| Sioux Center | 1 | 8,641 | 8,249 | 1.15% | 1,369 | 6.3 | City |
| Orange City | 2 | 6,437 | 6,277 | 0.63% | 1,397 | 4.6 | City |
| Rock Valley | 3 | 4,037 | 4,067 | -0.2% | 905 | 4.5 | City |
| Hawarden | 4 | 2,626 | 2,697 | -0.68% | 948 | 2.8 | City |
| Hull | 5 | 2,450 | 2,378 | 0.74% | 1,731 | 1.4 | City |
| Alton | 6 | 1,242 | 1,244 | -0.08% | 653 | 1.9 | City |
| Hospers | 7 | 701 | 719 | -0.71% | 1,328 | 0.5 | City |
| Boyden | 8 | 695 | 701 | -0.29% | 1,016 | 0.7 | City |
| Ireton | 9 | 575 | 587 | -0.52% | 564 | 1.0 | City |
| Granville | 10 | 300 | 311 | -0.99% | 1,031 | 0.3 | City |
| Maurice | 11 | 273 | 268 | 0.37% | 453 | 0.6 | City |
| Matlock | 12 | 77 | 76 | 0% | 204 | 0.4 | City |
| Chatsworth | 13 | 74 | 74 | 0% | 149 | 0.5 | City |
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.
Sioux Center is the largest city in Sioux County.
Chatsworth is the smallest city in Sioux County.
There are 13 cities in Sioux County, Iowa.