Residents of Drummond — Sub-district I, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 24 | obrian | harriet | F | 50 | Roman Catholic | French | Ireland | No Occupation Listed | 73 |
| 25 | obrian | john | M | 13 | Roman Catholic | Irish | Ontario | No Occupation Listed | 73 |
| 23 | obrian | patrick | M | 62 | Roman Catholic | Irish | Ireland | Labourers nfs | 73 |
| 2 | obrien | annie | F | 15 | Roman Catholic | Irish | Ontario | No Occupation Listed | 73 |
| 4 | obrien | ellen | F | 18 | Roman Catholic | Irish | Ontario | No Occupation Listed | 73 |
| 5 | obrien | hanorah | F | 12 | Roman Catholic | Irish | Ontario | No Occupation Listed | 73 |
| 1 | obrien | josephine | F | 10 | Roman Catholic | Irish | Ontario | No Occupation Listed | 73 |
| 25 | oconer | daniel | M | 7 | Roman Catholic | Scottish | Ontario | No Occupation Listed | 206 |
| 21 | oconner | catherine | F | 23 | Roman Catholic | Scottish | Ontario | No Occupation Listed | 206 |
| 22 | oconner | margaret | F | 20 | Roman Catholic | Scottish | Ontario | No Occupation Listed | 206 |
| 20 | oconner | margerie | F | 25 | Roman Catholic | Scottish | Ontario | No Occupation Listed | 206 |
| 19 | oconner | maryanne | F | 48 | Roman Catholic | Scottish | Ontario | Farmers, general and nfs | 206 |
| 23 | oconner | teressa | F | 18 | Roman Catholic | Scottish | Ontario | No Occupation Listed | 206 |
| 24 | oconner | thomas | M | 16 | Roman Catholic | Scottish | Ontario | No Occupation Listed | 206 |
| 5 | oconnor | ann | F | 75 | Roman Catholic | Irish | Ireland | No Occupation Listed | 149 |
| 4 | oconnor | dennis | M | 67 | Roman Catholic | Irish | Ireland | Farmers, general and nfs | 149 |
| 6 | oconnor | sarah | F | 12 | Roman Catholic | Irish | Ontario | No Occupation Listed | 149 |