Residents of Cardwell — Sub-district M, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 3 | obrien | annie | F | 15 | Methodist | English | New Brunswick | No Occupation Listed | 46 |
| 23 | obrien | elizabeth | F | 45 | Methodist | English | New Brunswick | No Occupation Listed | 46 |
| 25 | obrien | ellen | F | 21 | Methodist | English | New Brunswick | No Occupation Listed | 46 |
| 1 | obrien | john | M | 19 | Methodist | English | New Brunswick | Government functionaries (nfs) | 46 |
| 24 | obrien | mary | F | 22 | Methodist | English | New Brunswick | No Occupation Listed | 46 |
| 2 | obrien | sarah | F | 17 | Methodist | English | New Brunswick | No Occupation Listed | 46 |