Residents of Thorold, Village — Sub-district I, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 19 | oates | john | M | 35 | Roman Catholic | English | Ontario | Labourers nfs | 385 |
| 17 | oats | ann | F | 22 | Roman Catholic | Irish | Ontario | No Occupation Listed | 361 |
| 16 | oats | daniel | M | 24 | Roman Catholic | Irish | Ontario | Labourers nfs | 361 |
| 15 | oats | elizabeth | F | 27 | Roman Catholic | Irish | Ontario | Servants nfs | 361 |
| 14 | oats | mary | F | 65 | Roman Catholic | Irish | Ontario | No Occupation Listed | 361 |
| 20 | oats | mary | F | 26 | Roman Catholic | English | Ontario | No Occupation Listed | 385 |
| 21 | oats | william | M | 1 | Roman Catholic | English | Ontario | No Occupation Listed | 385 |
| 16 | obrien | bridget | F | 58 | Roman Catholic | Irish | Ireland | No Occupation Listed | 47 |
| 21 | obrien | catherine | F | 78 | Roman Catholic | Irish | Ireland | No Occupation Listed | 30 |
| 22 | obrien | ellen | F | 55 | Roman Catholic | Irish | Ontario | No Occupation Listed | 30 |
| 4 | obrien | hanora | F | 34 | Roman Catholic | Irish | Ireland | No Occupation Listed | 105 |
| 15 | obrien | john | M | 65 | Roman Catholic | Irish | Ireland | Hirers out | 47 |
| 18 | obrien | john | M | 25 | Roman Catholic | Irish | Ontario | Teamsters (inc. mine driver, etc.) | 47 |
| 5 | obrien | mary | F | 7 | Roman Catholic | Irish | Ontario | No Occupation Listed | 105 |
| 6 | obrien | rose | F | 4 | Roman Catholic | Irish | Ontario | No Occupation Listed | 105 |
| 17 | obrien | susan | F | 33 | Roman Catholic | Irish | Ireland | No Occupation Listed | 47 |
| 20 | obrien | thomas | M | 80 | Roman Catholic | Irish | Ireland | Carpenters | 30 |
| 25 | oherron | daniel | M | 50 | Roman Catholic | Irish | Ireland | Labourers nfs | 373 |
| 18 | olsen | mary | F | 24 | Presbyterian | Swedish | Sweden | No Occupation Listed | 384 |
| 17 | olson | john | M | 28 | Presbyterian | Swedish | Sweden | Labourers nfs | 384 |
| 12 | omallia | annie | F | 13 | Roman Catholic | Irish | Ontario | No Occupation Listed | 166 |
| 9 | omallia | catharine | F | 30 | Roman Catholic | Irish | Ireland | No Occupation Listed | 166 |
| 14 | omallia | margaret | F | 3 | Roman Catholic | Irish | Ontario | No Occupation Listed | 166 |
| 10 | omallia | michael | M | 18 | Roman Catholic | Irish | Ontario | Labourers nfs | 166 |
| 8 | omallia | peter | M | 60 | Roman Catholic | Irish | Ireland | Labourers nfs | 166 |
| 11 | omallia | peter | M | 16 | Roman Catholic | Irish | Ontario | No Occupation Listed | 166 |
| 13 | omallia | rose | F | 10 | Roman Catholic | Irish | Ontario | No Occupation Listed | 166 |
| 4 | omelia | catharine | F | 20 | Roman Catholic | Irish | Ireland | Servants nfs | 183 |
| 1 | oneal | patrick | M | 29 | Roman Catholic | Irish | Ireland | Draughtsmen | 236 |
| 14 | oznns | annie | F | 7 | Methodist | English | Ontario | No Occupation Listed | 263 |
| 10 | oznns | george | M | 33 | Methodist | English | Guernsey | Journalists, reporters | 263 |
| 12 | oznns | george | M | 12 | Methodist | English | Guernsey | No Occupation Listed | 263 |
| 11 | oznns | isabela | F | 36 | Methodist | English | Guernsey | Milliners | 263 |
| 16 | oznns | john | M | 3 | Methodist | English | Ontario | No Occupation Listed | 263 |
| 13 | oznns | lilian | F | 10 | Methodist | English | Guernsey | No Occupation Listed | 263 |
| 17 | oznns | thomas | M | 1 | Methodist | English | Ontario | No Occupation Listed | 263 |
| 15 | oznns | william | M | 5 | Methodist | English | Ontario | No Occupation Listed | 263 |