Residents of Grimsby — Sub-district E, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 8 | obron | nelly | F | 13 | Roman Catholic | Irish | Ontario | No Occupation Listed | 27 |
| 4 | oco_ | bartholemew | M | 49 | Roman Catholic | Irish | Ireland | Farmers, general and nfs | 125 |
| 5 | oco_ | catherine | F | 44 | Roman Catholic | Irish | Ireland | No Occupation Listed | 125 |
| 7 | oco_ | john | M | 3 | Roman Catholic | Irish | Ontario | No Occupation Listed | 125 |
| 6 | oco_ | william | M | 12 | Roman Catholic | Irish | Ontario | No Occupation Listed | 125 |
| 17 | oil | elgin | M | 32 | Universalist | German | Ontario | Farmers, general and nfs | 249 |
| 15 | oil | james | M | 60 | Universalist | German | Ontario | Farmers, general and nfs | 249 |
| 20 | oil | john | M | 4 | Universalist | German | Ontario | No Occupation Listed | 249 |
| 16 | oil | rachel | F | 59 | Universalist | English | Ontario | No Occupation Listed | 249 |
| 18 | oil | sarah | F | 30 | Universalist | German | Ontario | No Occupation Listed | 249 |
| 21 | oil | sophia | F | 2 | Universalist | German | Ontario | No Occupation Listed | 249 |
| 19 | oil | william | M | 6 | Universalist | German | Ontario | No Occupation Listed | 249 |
| 1 | oliver | james | M | 40 | Presbyterian | Scottish | Ontario | Farmers, general and nfs | 277 |
| 2 | oliver | sarah | F | 38 | Presbyterian | Scottish | Ontario | No Occupation Listed | 277 |
| 3 | oliver | susan | F | 54 | Presbyterian | Scottish | Ontario | No Occupation Listed | 277 |
| 17 | orth | charlie | M | 11 | Disciple of Christ | German | Ontario | No Occupation Listed | 103 |
| 15 | orth | francis | F | 20 | Disciple of Christ | German | Ontario | No Occupation Listed | 103 |
| 16 | orth | solomon | M | 18 | Disciple of Christ | German | Ontario | No Occupation Listed | 103 |
| 21 | overholt | john | M | 60 | Anglican | English | England | Labourers nfs | 244 |
| 23 | overholt | john | M | 24 | Anglican | English | England | No Occupation Listed | 244 |
| 22 | overholt | mary | F | 59 | Anglican | English | England | No Occupation Listed | 244 |