Residents of Oakville, T-V — Sub-district D, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 13 | obee | charlotte | F | 66 | Anglican | English | England | No Occupation Listed | 346 |
| 25 | oboyle | margaret | F | 62 | Roman Catholic | Irish | Ireland | No Occupation Listed | 122 |
| 1 | oboyle | mary | F | 23 | Roman Catholic | Irish | Ontario | No Occupation Listed | 122 |
| 24 | oboyle | patrick | M | 66 | Roman Catholic | Irish | Ireland | Labourers nfs | 122 |
| 7 | oconnel | catharine | F | 68 | Roman Catholic | Irish | Ireland | No Occupation Listed | 224 |
| 6 | oconnel | john | M | 4 | Roman Catholic | Irish | Ontario | No Occupation Listed | 224 |
| 1 | odonnel | mary | F | 7 | Roman Catholic | Irish | Ontario | No Occupation Listed | 237 |
| 12 | olephant | amanda | F | 27 | Wesleyan Methodist | German | Ontario | No Occupation Listed | 29 |
| 14 | olephant | charles | M | 23 | Wesleyan Methodist | German | Ontario | Tinsmiths and Tinners and Tinkers | 29 |
| 10 | olephant | duncan | M | 62 | Wesleyan Methodist | German | Ontario | Hotel Keepers and Managers | 29 |
| 11 | olephant | elisabeth | F | 54 | Wesleyan Methodist | German | Ontario | No Occupation Listed | 29 |
| 13 | olephant | isabella | F | 25 | Wesleyan Methodist | German | Ontario | No Occupation Listed | 29 |
| 2 | oliver | byron | M | 15 | Methodist | Scottish | Ontario | Clerk, nfs | 348 |
| 1 | oliver | henrietta | F | 17 | Methodist | Scottish | Ontario | No Occupation Listed | 348 |
| 3 | oliver | herbert | M | 11 | Methodist | Scottish | Ontario | No Occupation Listed | 348 |
| 25 | oliver | susan | F | 34 | Methodist | Scottish | Ontario | Dealer, merchant etc. (Wholesale & retail trade) | 348 |
| 7 | oneil | jessie | F | 34 | Roman Catholic | Irish | Ontario | No Occupation Listed | 284 |
| 19 | oneil | mary | F | 23 | Roman Catholic | Irish | Ontario | Servants nfs | 264 |
| 10 | oneil | may | F | 0 | Roman Catholic | Irish | Ontario | No Occupation Listed | 284 |
| 8 | oneil | nellie | F | 15 | Roman Catholic | Irish | United States | No Occupation Listed | 284 |
| 6 | oneil | patrick | M | 35 | Roman Catholic | Irish | Ireland | Bricklayers | 284 |
| 9 | oneil | thomas | M | 6 | Roman Catholic | Irish | United States | No Occupation Listed | 284 |
| 10 | oreilly | terence | M | 35 | Roman Catholic | Irish | Ireland | Ministers of Religion | 239 |
| 5 | orr | caroline | F | 22 | Methodist | Irish | Ontario | No Occupation Listed | 96 |
| 6 | orr | malinda | F | 16 | Methodist | Irish | Ontario | No Occupation Listed | 96 |
| 3 | orr | maria | F | 55 | Methodist | Irish | Ontario | No Occupation Listed | 96 |
| 4 | orr | rowland | M | 20 | Methodist | Irish | Ontario | Printers nfs | 96 |
| 4 | ovas | c | F | 24 | Presbyterian | Scottish | Ontario | Dressmakers | 348 |