Residents of Mono — Sub-district E, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 22 | oliver | alexander | M | 22 | Presbyterian | Irish | Ontario | No Occupation Listed | 62 |
| 20 | oliver | elizabeth | F | 49 | Presbyterian | Irish | Ireland | No Occupation Listed | 62 |
| 21 | oliver | elizabeth | F | 23 | Presbyterian | Irish | Ontario | No Occupation Listed | 62 |
| 24 | oliver | margaret | F | 15 | Presbyterian | Irish | Ontario | No Occupation Listed | 62 |
| 19 | oliver | robert | M | 46 | Presbyterian | Irish | Ireland | Farmers, general and nfs | 62 |
| 23 | oliver | sarah | F | 20 | Presbyterian | Irish | Ontario | No Occupation Listed | 62 |
| 12 | onail | annie | F | 27 | Roman Catholic | Irish | Ireland | No Occupation Listed | 40 |
| 14 | onail | ellen | F | 5 | Roman Catholic | Irish | Ontario | No Occupation Listed | 40 |
| 11 | onail | felix | M | 40 | Roman Catholic | Irish | Ontario | Farmers, general and nfs | 40 |
| 16 | onail | felix | M | 1 | Roman Catholic | Irish | Ontario | No Occupation Listed | 40 |
| 13 | onail | mary | F | 7 | Roman Catholic | Irish | Ontario | No Occupation Listed | 40 |
| 15 | onail | thomas | M | 3 | Roman Catholic | Irish | Ontario | No Occupation Listed | 40 |
| 4 | orr | george | M | 6 | Presbyterian | Irish | Ontario | No Occupation Listed | 1 |
| 3 | orr | james | M | 7 | Presbyterian | Irish | Ontario | No Occupation Listed | 1 |
| 13 | orr | james | M | 23 | Presbyterian | Irish | Ontario | Farmers, general and nfs | 66 |
| 2 | orr | mary | F | 30 | Presbyterian | Irish | Ontario | No Occupation Listed | 1 |
| 14 | orr | mary | F | 21 | Presbyterian | Irish | Ontario | No Occupation Listed | 66 |
| 15 | orr | samuel | M | 1 | Presbyterian | Irish | Ontario | No Occupation Listed | 66 |
| 6 | orr | thomas | M | 0 | Presbyterian | Irish | Ontario | No Occupation Listed | 1 |
| 16 | orr | thomas | M | 0 | Presbyterian | Irish | Ontario | No Occupation Listed | 66 |
| 1 | orr | william | M | 29 | Presbyterian | Irish | Ontario | Farmers, general and nfs | 1 |
| 5 | orr | william | M | 3 | Presbyterian | Irish | Ontario | No Occupation Listed | 1 |