| City | County | 2026 Pop. ↓ |
|---|---|---|
| Omaha | Douglas County | 487,917 |
| Offutt AFB | Sarpy County | 5,898 |
| Ogallala | Keith County | 4,669 |
| O'Neill | Holt County | 3,564 |
| Ord | Valley County | 2,119 |
| Oakland | Burt County | 1,332 |
| Osceola | Polk County | 888 |
| Osmond | Pierce County | 804 |
| Oshkosh | Garden County | 764 |
| Oxford | Furnas County | 695 |
| Overton | Dawson County | 591 |
| Orchard | Antelope County | 350 |
| Orleans | Harlan County | 323 |
| Oakdale | Antelope County | 267 |
| Odell | Gage County | 256 |
| Overland | Hamilton County | 226 |
| Otoe | Otoe County | 169 |
| Oconto | Custer County | 141 |
| Ohiowa | Fillmore County | 121 |
| Odessa | Buffalo County | 113 |
| Octavia | Butler County | 106 |
| Oak | Nuckolls County | 50 |
| Ong | Clay County | 49 |
| Obert | Cedar County | 22 |