Residents of Madoc, Village — Sub-district D, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 11 | oconnor | david | M | 63 | Roman Catholic | Irish | Ireland | No Occupation Listed | 88 |
| 10 | oflynn | e | M | 50 | Episcopal Methodist | Irish | Ontario | banker | 193 |
| 11 | oflynn | elizabeth | F | 43 | Episcopal Methodist | English | Ontario | No Occupation Listed | 193 |
| 16 | oflynn | emma | F | 10 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 193 |
| 12 | oflynn | frank | M | 25 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 193 |
| 13 | oflynn | frederick | M | 21 | Episcopal Methodist | Irish | Ontario | Clerk, nfs | 193 |
| 14 | oflynn | harry | M | 19 | Episcopal Methodist | Irish | Ontario | Clerk, nfs | 193 |
| 15 | oflynn | lilly | F | 14 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 193 |
| 9 | oflynn | rebecca | F | 25 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 84 |
| 17 | oflynn | walter | M | 7 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 193 |
| 8 | oflynn | wm | M | 33 | Episcopal Methodist | Irish | Ontario | Dealer, merchant etc. (Wholesale & retail trade) | 84 |
| 19 | ohara | benson | M | 28 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 157 |
| 16 | oldfield | horace | M | 4 | Methodist | English | Ontario | No Occupation Listed | 183 |
| 15 | oldfield | john | M | 8 | Methodist | English | Ontario | No Occupation Listed | 183 |
| 14 | oldfield | rebecca | F | 26 | Methodist | English | England | No Occupation Listed | 183 |
| 17 | oldfield | walter | M | 2 | Methodist | English | Ontario | No Occupation Listed | 183 |
| 13 | oldfield | william | M | 30 | Methodist | English | England | No Occupation Listed | 183 |
| 12 | oreardon | james | M | 0 | Roman Catholic | Irish | Ontario | No Occupation Listed | 121 |
| 9 | oreardon | maggie | F | 28 | Roman Catholic | French | Ontario | No Occupation Listed | 121 |
| 7 | oreardon | michael | M | 30 | Roman Catholic | Irish | Ontario | Labourers nfs | 120 |
| 10 | oreardon | minnie | F | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 121 |
| 8 | oreardon | robert | M | 31 | Roman Catholic | Irish | Ontario | Labourers nfs | 121 |
| 11 | oreardon | william | M | 3 | Roman Catholic | Irish | Ontario | No Occupation Listed | 121 |
| 25 | orr | arthur | M | 7 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 186 |
| 1 | orr | florence | F | 3 | Methodist | Irish | Ontario | No Occupation Listed | 102 |
| 24 | orr | frank | M | 9 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 186 |
| 23 | orr | george | M | 14 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 186 |
| 24 | orr | john | M | 23 | Methodist | Irish | Ontario | Editors | 102 |
| 1 | orr | maria | F | 4 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 186 |
| 25 | orr | mary | F | 29 | Methodist | Irish | Ontario | No Occupation Listed | 102 |
| 22 | orr | mary | F | 32 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 186 |
| 2 | orr | nelly | F | 1 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 186 |
| 21 | orr | william | M | 44 | Episcopal Methodist | Irish | Ontario | Blacksmiths | 186 |