Residents of Warwick — Sub-district I, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 11 | oak | albert | M | 11 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 64 |
| 15 | oakes | thomas | M | 22 | Anglican | Irish | Ontario | Labourers nfs | 132 |
| 20 | oaks | edward | M | 0 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 45 |
| 11 | oaks | george | M | 13 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 239 |
| 21 | oaks | john | M | 35 | Episcopal Methodist | Irish | Ontario | Farmers, general and nfs | 46 |
| 22 | oaks | margaret | F | 34 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 46 |
| 19 | oaks | mary | F | 25 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 45 |
| 18 | oaks | theophilas | M | 29 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 45 |
| 14 | obrian | bridget | F | 42 | Roman Catholic | Irish | Ireland | No Occupation Listed | 287 |
| 16 | obrian | cornelius | M | 8 | Roman Catholic | Irish | Ontario | No Occupation Listed | 287 |
| 13 | obrian | john | M | 50 | Roman Catholic | Irish | Ireland | Farmers, general and nfs | 287 |
| 15 | obrian | micheal | M | 12 | Roman Catholic | Irish | Ontario | No Occupation Listed | 287 |
| 5 | oleary | agnes | F | 13 | Roman Catholic | Irish | Ontario | No Occupation Listed | 206 |
| 6 | oleary | daniel | M | 10 | Roman Catholic | Irish | Ontario | No Occupation Listed | 206 |
| 4 | oleary | james | M | 54 | Roman Catholic | Irish | Ireland | Farmers, general and nfs | 206 |
| 15 | omora | mary | F | 51 | Roman Catholic | English | England | No Occupation Listed | 210 |
| 16 | omora | william | M | 49 | Roman Catholic | English | England | Farmers, general and nfs | 210 |
| 4 | oneil | ellenor | F | 51 | Roman Catholic | Irish | Ireland | No Occupation Listed | 142 |
| 7 | oneil | ellenor | F | 19 | Roman Catholic | Irish | Ontario | No Occupation Listed | 142 |
| 9 | oneil | jane | F | 23 | Methodist | English | Ontario | No Occupation Listed | 308 |
| 8 | oneil | john | M | 17 | Roman Catholic | Irish | Ontario | No Occupation Listed | 142 |
| 5 | oneil | margaret | F | 23 | Roman Catholic | Irish | Ontario | No Occupation Listed | 142 |
| 10 | oneil | marshal | M | 17 | Methodist | Irish | Ontario | Ambiguous responses | 308 |
| 6 | oneil | mary | F | 20 | Roman Catholic | Irish | Ontario | No Occupation Listed | 142 |
| 8 | oneil | robert | M | 54 | Methodist | Irish | Ontario | Farmers, general and nfs | 308 |
| 12 | orr | elmor | M | 10 | Episcopal Methodist | Scottish | Ontario | No Occupation Listed | 160 |
| 9 | orr | james | M | 36 | Episcopal Methodist | Scottish | Ontario | Farmers, general and nfs | 160 |
| 13 | orr | james | M | 7 | Episcopal Methodist | Scottish | Ontario | No Occupation Listed | 160 |
| 10 | orr | jane | F | 39 | Episcopal Methodist | Scottish | Ontario | No Occupation Listed | 160 |
| 14 | orr | lottie | F | 5 | Episcopal Methodist | Scottish | Ontario | No Occupation Listed | 160 |
| 11 | orr | mary | F | 12 | Episcopal Methodist | Scottish | Ontario | No Occupation Listed | 160 |
| 15 | orr | robert | M | 3 | Episcopal Methodist | Scottish | Ontario | No Occupation Listed | 160 |