| Name | # Entries |
|---|---|
| Oades | 0 |
| Oaing | 0 |
| Oakenfall | 0 |
| Oakenful | 0 |
| Oakly | 2 |
| Oakley Hollow | 0 |
| Oakroot | 0 |
| Oanh | 0 |
| Oanca | 0 |
| Oaten Hepworth | 0 |
| Ochoge | 0 |
| Ochorowicz | 0 |
| Ochoterena | 0 |
| Ocinski | 0 |
| Ocipka | 0 |
| Ocean Pacifique | 0 |
| Ochavez | 0 |
| Ochnik | 0 |
| Ockers | 0 |
| Ochre | 2 |
| Ockford | 0 |
| Ocolisan | 0 |
| Ockerlander | 0 |
| Oconell | 0 |
| Oconnell | 11 |
| Ockinga | 0 |
| Ocktaviani | 0 |
| Ocloudy | 0 |
| O''''briend | 0 |
| O''brine | 0 |
| O''''brist | 0 |
| Obryan | 1 |
| Obrzut | 0 |
| Obst Farey | 0 |
| Obstoj | 0 |
| Obuch | 0 |
| Obulareddy | 0 |
| Obut | 0 |
| Obstoy | 0 |
| Obudzinski | 0 |
| O Byrne | 36 |
| O Brien | 901 |
| Oatway | 4 |
| Obadage | 0 |
| Obaed | 0 |
| Obadua | 0 |
| Obaidullah | 0 |
| Obando | 0 |
| Oballoker | 0 |
| Obani | 0 |
| Obata | 0 |
| Obbes | 0 |
| Obedoza | 0 |
| O''baugh | 0 |
| O''bediah | 0 |
| Obeidy | 0 |
| Oberholster | 0 |
| Oberholzner | 0 |
| Oberklaid | 0 |
| Oberli | 0 |
| Obermeder | 0 |
| Obermuller | 0 |
| O''bernier | 0 |
| Obersnell | 0 |
| Oberscheidt | 0 |
| Oberti | 0 |
| Obialor | 0 |
| Obic | 0 |
| O''biegly | 0 |
| O''''biobhain | 0 |
| Obino | 0 |
| Obkircher | 0 |
| Oblak | 1 |
| Oblea | 0 |
| Obleshchuk | 0 |