| Modern Name | Original (Mawer) | Meaning (Mawer) | Notes | OS Zone | OS Ref |
|---|---|---|---|---|---|
| Oakwood | ac wudu | oak wood | NY | 950657 | |
| Old Bewick | beo wic | bee farm/dwelling | NU | 075215 | |
| Ord Mains | ord | point or corner of land | NT | 974507 | |
| Otterburn | oter burna | otter stream | NY | 885933 | |
| Ouse Burn | ? | Celtic river-name | NZ | 186696 | |
| Outchester | ule ceaster | owl chester | NU | 140334 | |
| Ovingham | Ofinga ham | homestead of the sons of Ofa | NZ | 085638 | |
| Ovington | Ofing tun | farm of Ofa | NZ | 066637 |