According to the 1940 census, Olson was the most common last name beginning with the letter 'O', followed by Owens and Oliver. Click on the names below to learn more about their meaning, history and origins.
| Surname | Rank* |
|---|---|
| Olson | 1 |
| Owens | 2 |
| Oliver | 3 |
| O'brien | 4 |
| Owen | 5 |
| Olsen | 6 |
| Osborne | 7 |
| O'connor | 8 |
| Orr | 9 |
| Osborn | 10 |
| Ortiz | 11 |
| Ott | 12 |
| Otto | 13 |
| O'donnell | 14 |
| O'connell | 15 |
* Based on population in the 1940 U.S. Census