Residents of Hamilton, Ward—Quartier No. 4 — Sub-district D, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 10 | obrien | edward | M | 45 | Roman Catholic | Irish | United States | Pedlars and hawkers | 239 |
| 15 | obrien | james | M | 32 | Roman Catholic | Irish | Ireland | Labourers nfs | 100 |
| 19 | obrien | james | M | 3 | Roman Catholic | Irish | Ontario | No Occupation Listed | 100 |
| 16 | obrien | mary | F | 29 | Roman Catholic | Irish | Ireland | No Occupation Listed | 100 |
| 18 | obrien | mary | F | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 100 |
| 17 | obrien | patrick | M | 8 | Roman Catholic | Irish | Ontario | No Occupation Listed | 100 |
| 20 | obrien | william | M | 1 | Roman Catholic | Irish | Ontario | No Occupation Listed | 100 |
| 19 | oconnor | catherine | F | 20 | Roman Catholic | Irish | United States | No Occupation Listed | 164 |
| 20 | oconnor | ellen | F | 25 | Roman Catholic | Irish | United States | No Occupation Listed | 164 |
| 17 | oconnor | james | M | 52 | Roman Catholic | Irish | Ireland | Farm workers (dairy) | 164 |
| 18 | oconnor | mary | F | 45 | Roman Catholic | Irish | Ireland | No Occupation Listed | 164 |
| 2 | oconnors | catherine | F | 13 | Roman Catholic | Irish | Ontario | No Occupation Listed | 54 |
| 10 | okelly | daniel | M | 1 | Roman Catholic | Irish | Ontario | No Occupation Listed | 53 |
| 5 | okelly | denis | M | 30 | Roman Catholic | Irish | Ontario | Clerk, nfs | 53 |
| 8 | okelly | john | M | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 53 |
| 6 | okelly | kate | F | 30 | Roman Catholic | Irish | Ireland | No Occupation Listed | 53 |
| 7 | okelly | mary | F | 7 | Roman Catholic | Irish | Ontario | No Occupation Listed | 53 |
| 9 | okelly | thomas | M | 3 | Roman Catholic | Irish | Ontario | No Occupation Listed | 53 |
| 12 | oleary | elizabeth | F | 58 | Roman Catholic | Irish | Ireland | No Occupation Listed | 168 |
| 16 | oleary | james | M | 26 | Roman Catholic | Irish | England | Upholsterers except vehicle | 168 |
| 24 | oliver | annie | F | 5 | Methodist | English | Ontario | No Occupation Listed | 314 |
| 23 | oliver | charles | M | 7 | Methodist | English | Ontario | No Occupation Listed | 314 |
| 25 | oliver | ettie | F | 2 | Methodist | English | Ontario | No Occupation Listed | 314 |
| 21 | oliver | frederick | M | 10 | Methodist | English | Ontario | No Occupation Listed | 314 |
| 22 | oliver | lillie | F | 9 | Methodist | English | Ontario | No Occupation Listed | 314 |
| 20 | oliver | matilda | F | 32 | Methodist | French | Ontario | No Occupation Listed | 314 |
| 25 | olliver | isabella | F | 77 | Methodist | Scottish | Scotland | No Occupation Listed | 397 |
| 5 | olliver | kate | F | 21 | Baptist | English | Ontario | No Occupation Listed | 226 |
| 22 | ollman | annie | F | 8 | Lutheran | German | Ontario | No Occupation Listed | 392 |
| 25 | ollman | frank | M | 1 | Lutheran | German | Ontario | No Occupation Listed | 392 |
| 24 | ollman | george | M | 3 | Lutheran | German | Ontario | No Occupation Listed | 392 |
| 19 | ollman | henry | M | 46 | Roman Catholic | German | Germany | Brick and tile makers | 392 |
| 1 | ollman | infant | M | 0 | Lutheran | German | Ontario | No Occupation Listed | 392 |
| 21 | ollman | john | M | 14 | Lutheran | German | Ontario | No Occupation Listed | 392 |
| 20 | ollman | maria | F | 39 | Lutheran | German | Germany | No Occupation Listed | 392 |
| 23 | ollman | william | M | 5 | Lutheran | German | Ontario | No Occupation Listed | 392 |
| 21 | oloughin | james | M | 18 | Roman Catholic | Irish | Ontario | Bakers | 214 |
| 19 | olsan | charles | M | 23 | Lutheran | Danish | Denmark | Labourers nfs | 130 |
| 4 | omand | alex | M | 0 | Presbyterian | Scottish | Ontario | No Occupation Listed | 359 |
| 2 | omand | barbara | F | 13 | Presbyterian | Scottish | Ontario | No Occupation Listed | 359 |
| 25 | omand | fanny | F | 41 | Anglican | Scottish | Ireland | No Occupation Listed | 359 |
| 1 | omand | gilbert | M | 51 | Presbyterian | Scottish | Nova Scotia | Engine and locomotive builders | 359 |
| 24 | omand | james | M | 46 | Presbyterian | Scottish | Nova Scotia | Occupational title unclassifiable | 359 |
| 3 | omand | susan | F | 3 | Presbyterian | Scottish | Ontario | No Occupation Listed | 359 |
| 22 | oneal | ellen | F | 38 | Roman Catholic | Irish | Ireland | No Occupation Listed | 62 |
| 23 | oneal | john | M | 16 | Roman Catholic | Irish | Ontario | No Occupation Listed | 62 |
| 21 | oneal | thomas | M | 59 | Roman Catholic | Irish | Ireland | Blacksmiths | 62 |
| 20 | oneil | annie | F | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 33 |
| 7 | oneil | bridget | F | 83 | Roman Catholic | Irish | Ireland | No Occupation Listed | 402 |
| 19 | oneil | ellen | F | 8 | Roman Catholic | Irish | Ontario | No Occupation Listed | 33 |
| 5 | oneil | james | M | 13 | Roman Catholic | Irish | Ontario | No Occupation Listed | 402 |
| 6 | oneil | margaret | F | 11 | Roman Catholic | Irish | Ontario | No Occupation Listed | 402 |
| 17 | oneil | margaret | F | 15 | Roman Catholic | Irish | Ontario | No Occupation Listed | 33 |
| 4 | oneil | mary | F | 50 | Roman Catholic | Irish | Ireland | No Occupation Listed | 402 |
| 16 | oneil | mary | F | 40 | Roman Catholic | Irish | Ireland | No Occupation Listed | 33 |
| 18 | oneil | mary | F | 9 | Roman Catholic | Irish | Ontario | No Occupation Listed | 33 |
| 3 | oneil | michael | M | 50 | Roman Catholic | Irish | Ireland | Farmers, general and nfs | 402 |
| 15 | oneil | patrick | M | 39 | Roman Catholic | Irish | Ireland | Labourers nfs | 33 |
| 8 | orielly | bridget | F | 40 | Roman Catholic | Irish | Ireland | No Occupation Listed | 80 |
| 16 | orielly | catherine | F | 4 | Roman Catholic | Irish | Ontario | No Occupation Listed | 80 |
| 9 | orielly | donald | M | 20 | Roman Catholic | Irish | Ontario | No Occupation Listed | 80 |
| 13 | orielly | edward | M | 11 | Roman Catholic | Irish | Ontario | No Occupation Listed | 80 |
| 10 | orielly | ellen | F | 18 | Roman Catholic | Irish | Ontario | No Occupation Listed | 80 |
| 15 | orielly | james | M | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 80 |
| 11 | orielly | john | M | 15 | Roman Catholic | Irish | Ontario | Labourers nfs | 80 |
| 7 | orielly | paterick | M | 49 | Roman Catholic | Irish | Ireland | Labourers nfs | 80 |
| 12 | orielly | paterick | M | 13 | Roman Catholic | Irish | Ontario | No Occupation Listed | 80 |
| 14 | orielly | thomas | M | 8 | Roman Catholic | Irish | Ontario | No Occupation Listed | 80 |
| 13 | orr | alfred | M | 12 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 18 |
| 19 | orr | catherine | F | 29 | Roman Catholic | English | England | No Occupation Listed | 96 |
| 22 | orr | catherine | F | 8 | Roman Catholic | Irish | Ontario | No Occupation Listed | 96 |
| 15 | orr | eddie | M | 10 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 18 |
| 14 | orr | edith | F | 14 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 18 |
| 23 | orr | helen | F | 3 | Roman Catholic | Irish | Ontario | No Occupation Listed | 96 |
| 19 | orr | herbert | M | 1 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 18 |
| 11 | orr | isabella | F | 34 | Wesleyan Methodist | Irish | Quebec | No Occupation Listed | 18 |
| 10 | orr | jacob | M | 38 | Presbyterian | Irish | New Brunswick | Metal moulders and coremakers and workers in… | 18 |
| 17 | orr | john | M | 6 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 18 |
| 18 | orr | john | M | 42 | Roman Catholic | Irish | Ireland | Labourers nfs | 96 |
| 21 | orr | john | M | 10 | Roman Catholic | Irish | Ontario | No Occupation Listed | 96 |
| 24 | orr | joseph | M | 0 | Roman Catholic | Irish | Ontario | No Occupation Listed | 96 |
| 16 | orr | joshua | M | 7 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 18 |
| 18 | orr | maggie | F | 3 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 18 |
| 20 | orr | mary | F | 11 | Roman Catholic | Irish | Ontario | No Occupation Listed | 96 |
| 12 | orr | william | M | 16 | Wesleyan Methodist | Irish | Ontario | No Occupation Listed | 18 |
| 1 | oshea | catherine | F | 40 | Roman Catholic | Irish | Ireland | No Occupation Listed | 223 |
| 5 | oshea | catherine | F | 2 | Roman Catholic | Irish | Ontario | No Occupation Listed | 223 |
| 4 | oshea | mary | F | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 223 |
| 25 | oshea | patrick | M | 60 | Roman Catholic | Irish | Ireland | Labourers nfs | 223 |
| 2 | oshea | peter | M | 10 | Roman Catholic | Irish | Ontario | No Occupation Listed | 223 |
| 3 | oshea | tracey | F | 4 | Roman Catholic | Irish | Ontario | No Occupation Listed | 223 |
| 19 | osullivan | mary | F | 76 | Roman Catholic | Irish | Ireland | No Occupation Listed | 356 |
| 23 | overeud | ethel | F | 2 | Anglican | Irish | Ontario | No Occupation Listed | 222 |
| 22 | overeud | maria | F | 26 | Anglican | English | West Indies | No Occupation Listed | 222 |
| 21 | overeud | miles | M | 30 | Anglican | Irish | England | Machinists | 222 |
| 18 | owen | george | M | 10 | Presbyterian | English | Ontario | No Occupation Listed | 390 |
| 14 | owen | henryetta | F | 47 | Presbyterian | English | England | No Occupation Listed | 390 |
| 13 | owen | james | M | 43 | Presbyterian | English | England | Metal rollers | 390 |
| 15 | owen | james | M | 24 | Presbyterian | English | England | Labourers nfs | 390 |
| 19 | owen | sarah | F | 10 | Presbyterian | English | Ontario | No Occupation Listed | 390 |
| 17 | owen | thomas | M | 13 | Presbyterian | English | England | No Occupation Listed | 390 |
| 16 | owen | william | M | 16 | Presbyterian | English | England | No Occupation Listed | 390 |