| NAME | TOWN |
| O'BRIEN | Albion Barre Carlton Murray Ridgeway Shelby |
| O'CONNELL | Ridgeway Shelby |
| O'CONNOR | Shelby |
| O'DONNELL | Ridgeway Shelby |
| O'FARRELL | Ridgeway Yates |
| O'FLAHERTY | Ridgeway |
| O'GRADY | Ridgeway |
| O'HARA | Shelby |
| O'HARROW | Gaines |
| O'MALLEY | Barre Ridgeway Shelby |
| O'MARA | Ridgeway |
| O'NEIL | Albion Clarendon |
| O'REILLY | Gaines Ridgeway |
| O'SHEA | Ridgeway |
| O'SULLIVAN | Ridgeway |
| OAKES | Ridgeway |
| OATMAN | Ridgeway |
| ODELL | Kendall Murray |
| ODERKIRK | Clarendon Ridgeway |
| OGDEN | Barre Clarendon Ridgeway Yates |
| OGLEY | Barre |
| OLDS | Kendall Ridgeway |
| OLMSTEAD | Albion Clarendon Yates |
| OMAN | Clarendon |
| ONDERDONK | Gaines Murray Yates |
| OPP/OPERST | Murray |
| ORCUTT | Clarendon Yates |
| ORR | Murray |
| ORSLAND | Kendall |
| ORTON | Barre |
| OSBORN | Carlton Gaines Kendall Murray Ridgeway |
| OSTRANDER | Carlton Gaines Murray Ridgeway |
| OSTROM | Ridgeway |
| OUGH | Albion |
| OVER | Murray |
| OVERFIELD | Murray |
| OWEN/OWENS | Albion Barre Kendall Shelby |