Residents of Harwich — Sub-district D, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 8 | obrien | charles | M | 34 | Methodist | Irish | United States | Farmers, general and nfs | 81 |
| 12 | obrien | george | M | 13 | Methodist | Irish | Ontario | No Occupation Listed | 81 |
| 11 | obrien | michael | M | 15 | Methodist | Irish | Ontario | Farmers, general and nfs | 81 |
| 10 | obrien | robert | M | 21 | Methodist | Irish | Ontario | Farmers, general and nfs | 81 |
| 9 | obrien | susan | F | 38 | Methodist | Irish | Ontario | No Occupation Listed | 81 |
| 7 | ogle | ellen | F | 35 | Anglican | Irish | Ontario | Farmers, general and nfs | 8 |
| 6 | ogle | george | M | 38 | Anglican | Irish | Ontario | Farmers, general and nfs | 8 |
| 11 | ogle | george | M | 7 | | Blank | Ontario | No Occupation Listed | 8 |
| 8 | ogle | john | M | 15 | | Blank | Ontario | No Occupation Listed | 8 |
| 10 | ogle | jonathan | M | 11 | | Blank | Ontario | No Occupation Listed | 8 |
| 12 | ogle | margaret | F | 5 | | Blank | Ontario | No Occupation Listed | 8 |
| 9 | ogle | oliver | M | 13 | | Blank | Ontario | No Occupation Listed | 8 |
| 13 | ogle | thomas | M | 3 | | Blank | Ontario | No Occupation Listed | 8 |
| 23 | okeefe | bridget | F | 24 | Roman Catholic | Irish | Ontario | No Occupation Listed | 136 |
| 6 | okeefe | edward | M | 33 | Roman Catholic | Irish | Ontario | Farmers, general and nfs | 128 |
| 21 | okeefe | edward | M | 33 | Roman Catholic | Irish | Ontario | Farmers, general and nfs | 136 |
| 25 | okeefe | ellen | F | 57 | Roman Catholic | Irish | Ireland | No Occupation Listed | 136 |
| 8 | okeefe | isabella | F | 4 | Roman Catholic | Irish | Ontario | No Occupation Listed | 128 |
| 9 | okeefe | james | M | 1 | Roman Catholic | Irish | Ontario | No Occupation Listed | 128 |
| 11 | okeefe | james | M | 58 | Roman Catholic | Irish | Ireland | Farmers, general and nfs | 129 |
| 22 | okeefe | james | M | 30 | Roman Catholic | Irish | Ontario | Farmers, general and nfs | 136 |
| 14 | okeefe | joseph | M | 21 | Roman Catholic | Irish | Ontario | No Occupation Listed | 129 |
| 12 | okeefe | julia | F | 58 | Roman Catholic | Irish | Ireland | No Occupation Listed | 129 |
| 24 | okeefe | maria | F | 17 | Roman Catholic | Irish | Ontario | No Occupation Listed | 136 |
| 7 | okeefe | mary | F | 33 | Roman Catholic | Scottish | Quebec | No Occupation Listed | 128 |
| 13 | okeefe | mary | F | 28 | Roman Catholic | Irish | Ontario | No Occupation Listed | 129 |
| 16 | old | anne | F | 38 | Methodist | English | Ontario | No Occupation Listed | 152 |
| 21 | old | charles | M | 0 | Methodist | English | Ontario | No Occupation Listed | 152 |
| 19 | old | clarabell | F | 8 | Methodist | English | Ontario | No Occupation Listed | 152 |
| 20 | old | herbert | M | 4 | Methodist | English | Ontario | No Occupation Listed | 152 |
| 17 | old | martin | M | 11 | Methodist | English | Ontario | No Occupation Listed | 152 |
| 18 | old | walter | M | 9 | Methodist | English | Ontario | No Occupation Listed | 152 |
| 15 | old | william | M | 36 | Methodist | English | Ontario | Farmers, general and nfs | 152 |
| 9 | oldershaw | charles | M | 15 | Methodist | English | Ontario | No Occupation Listed | 186 |
| 11 | oldershaw | daisey | F | 7 | Methodist | English | Ontario | No Occupation Listed | 186 |
| 6 | oldershaw | eliza | F | 22 | Methodist | English | Ontario | No Occupation Listed | 186 |
| 4 | oldershaw | gare | M | 62 | Methodist | English | England | Mason nfs or combined | 186 |
| 7 | oldershaw | isaac | M | 19 | Methodist | English | Ontario | Mason nfs or combined | 186 |
| 12 | oldershaw | john | M | 29 | Methodist | English | Ontario | Mason nfs or combined | 186 |
| 5 | oldershaw | mary | F | 52 | Methodist | English | Ontario | No Occupation Listed | 186 |
| 8 | oldershaw | minnie | F | 15 | Methodist | English | Ontario | No Occupation Listed | 186 |
| 10 | oldershaw | thomas | M | 10 | Methodist | English | Ontario | No Occupation Listed | 186 |
| 24 | ollett | john | M | 27 | Methodist | English | England | Farmers, general and nfs | 26 |
| 13 | osterhout | albert | M | 9 | Methodist | German | Ontario | No Occupation Listed | 43 |
| 17 | osterhout | charles | M | 0 | Methodist | German | Ontario | No Occupation Listed | 43 |
| 11 | osterhout | ellie | F | 13 | Methodist | German | Ontario | No Occupation Listed | 43 |
| 16 | osterhout | emma | F | 3 | Methodist | German | Ontario | No Occupation Listed | 43 |
| 14 | osterhout | john | M | 7 | Methodist | German | Ontario | No Occupation Listed | 43 |
| 10 | osterhout | mary | F | 32 | Methodist | German | Ontario | No Occupation Listed | 43 |
| 12 | osterhout | mary | F | 11 | Methodist | German | Ontario | No Occupation Listed | 43 |
| 15 | osterhout | william | M | 5 | Methodist | German | Ontario | No Occupation Listed | 43 |
| 9 | osterhout | wm | M | 34 | Methodist | German | Quebec | Railway builders, workers and labourers | 43 |
| 8 | outhouse | elizabeth | F | 25 | Baptist | German | Ontario | Teachers (unspecified) | 42 |
| 17 | overlwitt | ellen | F | 23 | Roman Catholic | Irish | Nova Scotia | Servants nfs | 135 |
| 18 | overlwitt | nellie | F | 0 | Roman Catholic | Irish | Nova Scotia | No Occupation Listed | 135 |
| 4 | oxendine | charles | M | 13 | Methodist | African Origins | Ontario | No Occupation Listed | 226 |