Residents of Alliston, T-V — Sub-district G, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 18 | obrien | eliz | F | 0 | Roman Catholic | Irish | Ontario | No Occupation Listed | 65 |
| 14 | obrien | john | M | 39 | Roman Catholic | Irish | Ontario | Hotel Keepers and Managers | 65 |
| 17 | obrien | john | M | 2 | Roman Catholic | Irish | Ontario | No Occupation Listed | 65 |
| 15 | obrien | mary | F | 32 | Roman Catholic | Irish | Ontario | No Occupation Listed | 65 |
| 16 | obrien | wm | M | 4 | Roman Catholic | Irish | Ontario | No Occupation Listed | 65 |
| 16 | oconnor | bridget | F | 74 | Roman Catholic | Irish | Ireland | No Occupation Listed | 209 |
| 15 | oconnor | michael | M | 81 | Roman Catholic | Irish | Ireland | No Occupation Listed | 209 |
| 17 | oconnor | wm | M | 23 | Roman Catholic | Irish | Ontario | Carpenters | 209 |
| 21 | oloane | john | M | 29 | Roman Catholic | Irish | Ontario | Salespeople, wholesale or retail trade | 128 |
| 5 | orchard | fannie | F | 19 | Methodist | Irish | Ontario | Dressmakers | 122 |