Residents of London, Ward—Quartier No. 4 — Sub-district D, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 3 | obyrne | james | M | 36 | Methodist | Irish | Ireland | Carpenters | 89 |
| 23 | ogready | ellen | F | 26 | Roman Catholic | Irish | Ontario | Dressmakers | 171 |
| 12 | okeefe | william | M | 38 | Roman Catholic | Irish | Ireland | Ministers of Religion | 217 |
| 13 | omahony | william | M | 36 | Roman Catholic | Irish | Ireland | Ministers of Religion | 217 |
| 11 | omeara | elizabeth | F | 22 | Roman Catholic | Irish | Ireland | Servants nfs | 67 |
| 15 | omond | andrew | M | 4 | Presbyterian | Scottish | Ontario | No Occupation Listed | 222 |
| 13 | omond | catherine | F | 29 | Presbyterian | French | Quebec | No Occupation Listed | 222 |
| 12 | omond | hugh | M | 45 | Presbyterian | Scottish | Scotland | Messengers | 222 |
| 14 | omond | hugh | M | 6 | Presbyterian | Scottish | Ontario | No Occupation Listed | 222 |
| 16 | omond | john | M | 0 | Presbyterian | Scottish | Ontario | No Occupation Listed | 222 |
| 13 | oriely | ann | F | 35 | Roman Catholic | Irish | Ontario | Servants nfs | 134 |
| 23 | oriely | fanny | F | 23 | Anglican | Irish | Ontario | No Occupation Listed | 20 |
| 24 | oriely | walter | M | 30 | Roman Catholic | Irish | Ontario | Cigar makers | 20 |
| 22 | oriely | william | M | 28 | Roman Catholic | Irish | Ontario | Labourers nfs | 20 |
| 7 | osier | lanis | M | 21 | Roman Catholic | French | Ontario | Labourers nfs | 18 |