Residents of Trois-Rivières, St. Louis, Ward—Quartier — Sub-district B, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 24 | olivier | arthur | M | 26 | Roman Catholic | French | Quebec | avocat | 64 |
| 20 | oreiley | james | M | 8 | Roman Catholic | Irish | Quebec | No Occupation Listed | 212 |
| 18 | oreilley | joseph | M | 13 | Roman Catholic | Irish | Quebec | No Occupation Listed | 212 |
| 17 | oreilley | mary | F | 33 | Roman Catholic | Irish | Ontario | No Occupation Listed | 212 |
| 19 | oreilley | mary | F | 10 | Roman Catholic | Irish | Quebec | No Occupation Listed | 212 |
| 22 | oreilley | percy | M | 4 | Roman Catholic | Irish | Quebec | No Occupation Listed | 212 |
| 16 | oreilley | thomas | M | 40 | Roman Catholic | Irish | Ontario | Contractors (and builders, U.S.) | 212 |
| 21 | oreilley | william | M | 6 | Roman Catholic | Irish | Quebec | No Occupation Listed | 212 |
| 17 | ouillette | george | M | 17 | Roman Catholic | French | Quebec | No Occupation Listed | 173 |
| 15 | ouillette | philomene | F | 45 | Roman Catholic | French | Quebec | No Occupation Listed | 173 |
| 16 | ouillette | prudense | F | 19 | Roman Catholic | French | Quebec | No Occupation Listed | 173 |