Zip Code | City | Population |
|---|---|---|
| 51106 | Sioux City | 27,652 |
| 51104 | Sioux City | 22,759 |
| 51103 | Sioux City | 17,005 |
| 51105 | Sioux City | 11,214 |
| 51054 | Sergeant Bluff | 5,416 |
| 51039 | Moville | 2,648 |
| 51030 | Lawton | 1,586 |
| 51055 | Sloan | 1,271 |
| 51016 | Correctionville | 1,118 |
| 51101 | Sioux City | 1,070 |
| 51026 | Hornick | 1,057 |
| 51052 | Salix | 1,001 |
| 51004 | Anthon | 863 |
| 51007 | Bronson | 569 |
| 51019 | Danbury | 566 |
| 51048 | Pierson | 525 |
| 51056 | Smithland | 464 |
| 51044 | Oto | 216 |
| 51111 | Sioux City | 124 |
| 51015 | Climbing Hill | 71 |