Residents of London, Ward—Quartier No. 1 — Sub-district A, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 5 | obrian | elizabeth | F | 40 | Presbyterian | Scottish | Ontario | No Occupation Listed | 97 |
| 7 | obrian | ellen | F | 65 | Roman Catholic | Irish | Ireland | No Occupation Listed | 98 |
| 6 | obrian | john | M | 12 | Presbyterian | Irish | Ontario | No Occupation Listed | 97 |
| 23 | oconner | john | M | 34 | Roman Catholic | Irish | Ontario | Printers nfs | 125 |
| 24 | oconner | sofronie | F | 25 | Roman Catholic | French | United States | No Occupation Listed | 125 |
| 13 | oconnor | elizabeth | F | 19 | Roman Catholic | Irish | Ontario | No Occupation Listed | 192 |
| 11 | oconnor | james | M | 50 | Roman Catholic | Irish | Ireland | Carpenters | 192 |
| 12 | oconnor | margaret | F | 40 | Roman Catholic | Irish | Ireland | No Occupation Listed | 192 |
| 17 | ohagan | alice | F | 5 | Roman Catholic | Irish | Ontario | No Occupation Listed | 238 |
| 12 | ohagan | james | M | 20 | Roman Catholic | Irish | Jersey | Printers nfs | 238 |
| 11 | ohagan | julia | F | 40 | Roman Catholic | Irish | Ireland | No Occupation Listed | 238 |
| 13 | ohagan | julia | F | 16 | Roman Catholic | Irish | Ireland | Dressmakers | 238 |
| 16 | ohagan | mary | F | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 238 |
| 15 | ohagan | michael | M | 10 | Roman Catholic | Irish | Ontario | No Occupation Listed | 238 |
| 14 | ohagan | sarah | F | 13 | Roman Catholic | Irish | Ontario | Box makers (wood) | 238 |
| 13 | omeara | annie | F | 24 | Roman Catholic | Irish | Ireland | No Occupation Listed | 5 |
| 7 | omeara | catherine | F | 63 | Roman Catholic | Irish | Ireland | No Occupation Listed | 5 |
| 14 | omeara | elena | F | 20 | Roman Catholic | Irish | Ireland | No Occupation Listed | 5 |
| 11 | omeara | james | M | 21 | Roman Catholic | Irish | Ireland | No Occupation Listed | 5 |
| 8 | omeara | john | M | 35 | Roman Catholic | Irish | Ireland | Packers | 5 |
| 9 | omeara | martin | M | 33 | Roman Catholic | Irish | Ireland | Packers | 5 |
| 12 | omeara | mary | F | 26 | Roman Catholic | Irish | Ireland | No Occupation Listed | 5 |
| 10 | omeara | michael | M | 28 | Roman Catholic | Irish | Ireland | Packers | 5 |
| 2 | oneil | john | M | 30 | Anglican | Irish | Ontario | Veterinarians | 137 |
| 4 | oneil | kate | F | 2 | Anglican | Irish | Ontario | No Occupation Listed | 137 |
| 12 | oneil | mary | F | 35 | Roman Catholic | Irish | Ireland | Servants nfs | 267 |
| 3 | oneil | sarah | F | 26 | Anglican | Irish | Ontario | No Occupation Listed | 137 |
| 15 | ormond | mahala | F | 36 | Anglican | English | Ontario | Tailors and tailoresses | 226 |
| 15 | osboldstone | emma | F | 41 | Anglican | English | England | No Occupation Listed | 110 |
| 13 | osboldstone | nancy | F | 45 | Anglican | English | England | No Occupation Listed | 110 |
| 12 | osboldstone | william | M | 43 | Anglican | English | England | Clerk, nfs | 110 |
| 14 | osboldstone | william | M | 13 | Anglican | English | England | No Occupation Listed | 110 |
| 10 | osborn | fannie | F | 28 | Methodist | English | England | No Occupation Listed | 92 |
| 9 | osborn | john | M | 29 | Methodist | English | England | Dealer, merchant etc. (Wholesale & retail trade) | 92 |