Residents of Hamilton, Ward—Quartier No. 1 — Sub-district A, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 13 | oatrie | mary | F | 39 | Presbyterian | Scottish | Scotland | No Occupation Listed | 21 |
| 24 | oconnor | agnes | F | 1 | Roman Catholic | Irish | Ontario | No Occupation Listed | 260 |
| 20 | oconnor | catherine | F | 12 | Roman Catholic | Irish | Ontario | No Occupation Listed | 260 |
| 17 | oconnor | daniel | M | 45 | Roman Catholic | Irish | Ireland | Labourers nfs | 260 |
| 18 | oconnor | ellen | F | 34 | Roman Catholic | Irish | Ireland | No Occupation Listed | 260 |
| 23 | oconnor | esther | F | 3 | Roman Catholic | Irish | Ontario | No Occupation Listed | 260 |
| 19 | oconnor | john | M | 13 | Roman Catholic | Irish | Ontario | Hat makers | 260 |
| 24 | oconnor | patrick | M | 31 | Roman Catholic | Irish | Ireland | Labourers nfs | 208 |
| 22 | oconnor | patrick | M | 8 | Roman Catholic | Irish | Ontario | No Occupation Listed | 260 |
| 21 | oconnor | timothy | M | 10 | Roman Catholic | Irish | Ontario | No Occupation Listed | 260 |
| 10 | odell | alexander | M | 13 | Anglican | Irish | Ontario | No Occupation Listed | 103 |
| 15 | odell | ebenezer | M | 3 | Anglican | Irish | Ontario | No Occupation Listed | 103 |
| 8 | odell | edmond | M | 37 | Anglican | Irish | Ireland | Bakers | 103 |
| 13 | odell | edmond | M | 6 | Anglican | Irish | Ontario | No Occupation Listed | 103 |
| 9 | odell | julia | F | 36 | Anglican | Irish | Ontario | No Occupation Listed | 103 |
| 14 | odell | katie | F | 4 | Anglican | Irish | Ontario | No Occupation Listed | 103 |
| 11 | odell | millicent | F | 11 | Anglican | Irish | Ontario | No Occupation Listed | 103 |
| 12 | odell | wilhelmina | F | 9 | Anglican | Irish | Ontario | No Occupation Listed | 103 |
| 7 | odew | annie | F | 39 | Roman Catholic | Irish | Ireland | Servants nfs | 56 |
| 18 | odey | mary | F | 67 | Roman Catholic | Irish | Ireland | No Occupation Listed | 146 |
| 19 | odey | nelly | F | 21 | Roman Catholic | Irish | Ontario | No Occupation Listed | 146 |
| 18 | odonnell | arthur | M | 16 | Roman Catholic | Irish | Ontario | No Occupation Listed | 140 |
| 21 | odonnell | florence | F | 7 | Roman Catholic | Irish | Ontario | No Occupation Listed | 140 |
| 22 | odonnell | howard | M | 1 | Roman Catholic | Irish | Ontario | No Occupation Listed | 140 |
| 17 | odonnell | joseph | M | 21 | Roman Catholic | Irish | Ontario | Bookkeepers nfs | 140 |
| 16 | odonnell | kate | F | 41 | Roman Catholic | Irish | Ireland | No Occupation Listed | 140 |
| 19 | odonnell | lillie | F | 12 | Roman Catholic | Irish | Ontario | No Occupation Listed | 140 |
| 15 | odonnell | patrick | M | 45 | Roman Catholic | Irish | Ireland | Clerk, nfs | 140 |
| 20 | odonnell | rosie | F | 9 | Roman Catholic | Irish | Ontario | No Occupation Listed | 140 |
| 20 | oflynn | helen | F | 19 | Roman Catholic | Irish | United States | No Occupation Listed | 173 |
| 22 | oflynn | james | M | 11 | Roman Catholic | Irish | Ontario | No Occupation Listed | 173 |
| 18 | oflynn | john | M | 55 | Roman Catholic | Irish | Ireland | Labourers nfs | 173 |
| 23 | oflynn | lawrence | M | 5 | Roman Catholic | Irish | Ontario | No Occupation Listed | 173 |
| 19 | oflynn | mary | F | 50 | Roman Catholic | Irish | Ireland | No Occupation Listed | 173 |
| 21 | oflynn | michael | M | 17 | Roman Catholic | Irish | Ontario | No Occupation Listed | 173 |
| 8 | oglivie | mary | F | 25 | Presbyterian | Scottish | Ontario | Servants nfs | 88 |
| 15 | ograthy | catharine | F | 50 | Roman Catholic | Irish | Ireland | No Occupation Listed | 200 |
| 16 | ograthy | mathew | M | 19 | Roman Catholic | Irish | Ontario | Printers nfs | 200 |
| 10 | oheir | arthur | M | 21 | Roman Catholic | Irish | Ontario | law student | 72 |
| 9 | oheir | fanny | F | 50 | Roman Catholic | Irish | England | No Occupation Listed | 72 |
| 8 | oheir | peter | M | 60 | Roman Catholic | Irish | Ireland | Customs officers | 72 |
| 8 | old | betsy | F | 45 | Methodist | English | Ontario | No Occupation Listed | 82 |
| 11 | old | elizabeth | F | 13 | Methodist | English | Ontario | No Occupation Listed | 82 |
| 12 | old | frederick | M | 10 | Methodist | English | Ontario | No Occupation Listed | 82 |
| 9 | old | john | M | 20 | Methodist | English | Ontario | Butchers | 82 |
| 14 | old | mable | F | 6 | Methodist | English | Ontario | No Occupation Listed | 82 |
| 13 | old | robert | M | 7 | Methodist | English | Ontario | No Occupation Listed | 82 |
| 7 | old | thomas | M | 58 | Methodist | English | England | Labourers nfs | 82 |
| 10 | old | william | M | 15 | Methodist | English | Ontario | Butchers | 82 |
| 23 | oneil | annie | F | 9 | Roman Catholic | Irish | Ontario | No Occupation Listed | 229 |
| 11 | oneil | arthur | M | 76 | Roman Catholic | Irish | Ireland | Tailors and tailoresses | 280 |
| 20 | oneil | bridget | F | 40 | Roman Catholic | Irish | Ireland | No Occupation Listed | 229 |
| 22 | oneil | bridget | F | 12 | Roman Catholic | Irish | Ontario | No Occupation Listed | 229 |
| 4 | oneil | celia | F | 21 | Roman Catholic | Irish | Ontario | No Occupation Listed | 175 |
| 2 | oneil | charles | M | 0 | Anglican | Irish | Ontario | No Occupation Listed | 110 |
| 12 | oneil | ellen | F | 50 | Roman Catholic | Irish | Ireland | No Occupation Listed | 280 |
| 1 | oneil | ethel | F | 2 | Anglican | Irish | Ontario | No Occupation Listed | 110 |
| 5 | oneil | felix | M | 45 | Roman Catholic | Irish | Ireland | Drivers (personal, for hire) | 157 |
| 24 | oneil | hannah | F | 27 | Roman Catholic | Irish | United States | No Occupation Listed | 110 |
| 3 | oneil | john | M | 26 | Roman Catholic | Irish | Ontario | No Occupation Listed | 175 |
| 19 | oneil | john | M | 45 | Roman Catholic | Irish | Ireland | Labourers nfs | 229 |
| 13 | oneil | john | M | 25 | Roman Catholic | Irish | Ontario | Occupational title unclassifiable | 280 |
| 23 | oneil | john | M | 32 | Anglican | Irish | Ontario | Printers nfs | 110 |
| 25 | oneil | john | M | 6 | Anglican | Irish | Ontario | No Occupation Listed | 110 |
| 24 | oneil | katie | F | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 229 |
| 25 | oneil | lizzie | F | 4 | Roman Catholic | Irish | Ontario | No Occupation Listed | 229 |
| 6 | oneil | maria | F | 28 | Roman Catholic | Irish | Ontario | No Occupation Listed | 157 |
| 14 | oneil | mary | F | 14 | Roman Catholic | Irish | Ontario | No Occupation Listed | 280 |
| 21 | oneil | michael | M | 19 | Roman Catholic | Irish | United States | Cigar makers | 229 |
| 5 | oneil | thomas | M | 0 | Roman Catholic | Irish | Ontario | No Occupation Listed | 175 |
| 22 | oreilly | mary | F | 25 | Roman Catholic | Irish | Ontario | Servants nfs | 3 |
| 8 | ormand | andrew | M | 8 | Presbyterian | Blank | — | No Occupation Listed | 316 |
| 9 | ormand | john | M | 11 | Presbyterian | Blank | — | No Occupation Listed | 316 |
| 11 | orton | mary | F | 43 | Anglican | English | England | Teachers (unspecified) | 315 |
| 4 | osborne | annie | F | 80 | Anglican | Irish | Ireland | No Occupation Listed | 288 |
| 12 | osler | ernest | M | 23 | Anglican | English | Ontario | Clerk, nfs | 172 |
| 1 | owens | george | M | 10 | Anglican | English | — | No Occupation Listed | 316 |