16 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Sioux City | 1 | 85,694 | 85,776 | -0.02% | 1,455 | 58.88 | City |
| Sergeant Bluff | 2 | 5,450 | 5,009 | 1.64% | 1,834 | 2.97 | City |
| Moville | 3 | 1,688 | 1,692 | -0.06% | 1,839 | 0.92 | City |
| Sloan | 4 | 1,064 | 1,049 | 0.28% | 1,841 | 0.58 | City |
| Lawton | 5 | 934 | 944 | -0.21% | 1,297 | 0.72 | City |
| Correctionville | 6 | 736 | 760 | -0.67% | 1,225 | 0.60 | City |
| Anthon | 7 | 524 | 541 | -0.57% | 743 | 0.70 | City |
| Pierson | 8 | 325 | 339 | -0.91% | 684 | 0.47 | City |
| Danbury | 9 | 306 | 318 | -0.65% | 756 | 0.41 | City |
| Salix | 10 | 298 | 300 | 0% | 176 | 1.70 | City |
| Bronson | 11 | 290 | 299 | -0.68% | 838 | 0.35 | City |
| Hornick | 12 | 248 | 255 | -0.4% | 808 | 0.31 | City |
| Cushing | 13 | 218 | 230 | -0.91% | 686 | 0.32 | City |
| Smithland | 14 | 180 | 187 | -0.55% | 561 | 0.32 | City |
| Climbing Hill | 15 | 89 | 86 | 7.23% | 69 | 1.28 | CDP |
| Oto | 16 | 67 | 71 | -1.47% | 249 | 0.27 | City |
Sioux City is the largest city in Woodbury County, with a population of 85,694.
Oto is the smallest city in Woodbury County.
There are 16 cities in Woodbury County, Iowa.