Residents of Welland, C — Sub-district F, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 5 | obrian | catharina | F | 0 | Roman Catholic | Irish | Ontario | No Occupation Listed | 377 |
| 3 | obrian | james | M | 36 | Roman Catholic | Irish | United States | Engineers (US) nfs | 377 |
| 4 | obrian | susan | F | 26 | Roman Catholic | Irish | Ontario | No Occupation Listed | 377 |
| 22 | obrion | cornelius | M | 15 | Roman Catholic | Irish | Ontario | No Occupation Listed | 331 |
| 24 | obrion | ellen | F | 13 | Roman Catholic | Irish | Ontario | No Occupation Listed | 331 |
| 21 | obrion | jeremiah | M | 16 | Roman Catholic | Irish | Ontario | Other crew of boats, ships, etc. | 331 |
| 20 | obrion | john | M | 19 | Roman Catholic | Irish | Ontario | Other crew of boats, ships, etc. | 331 |
| 25 | obrion | margaret | F | 65 | Roman Catholic | Irish | Ireland | No Occupation Listed | 331 |
| 23 | obrion | mary | F | 14 | Roman Catholic | Irish | Ontario | No Occupation Listed | 331 |
| 16 | oconnor | charles | M | 37 | Roman Catholic | Irish | Ireland | Labourers nfs | 90 |
| 7 | odlum | edward | M | 31 | Anglican | Irish | Ireland | Civil engineers | 252 |
| 9 | odlum | eleanor | F | 2 | Anglican | Irish | Ontario | No Occupation Listed | 252 |
| 8 | odlum | helen | F | 23 | Anglican | Irish | Ontario | No Occupation Listed | 252 |
| 25 | oliver | james | M | 60 | Anglican | Irish | Ontario | Labourers nfs | 111 |
| 1 | oliver | mary | F | 60 | Anglican | German | Ontario | No Occupation Listed | 111 |
| 6 | oneal | bertha | F | 1 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 67 |
| 4 | oneal | emma | F | 9 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 67 |
| 25 | oneal | james | M | 17 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 67 |
| 23 | oneal | john | M | 49 | Episcopal Methodist | Irish | Ireland | Seamen | 67 |
| 1 | oneal | lavina | F | 16 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 67 |
| 5 | oneal | martha | F | 7 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 67 |
| 2 | oneal | mary | F | 14 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 67 |
| 3 | oneal | matilda | F | 12 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 67 |
| 24 | oneal | sarah | F | 36 | Episcopal Methodist | Irish | Ontario | No Occupation Listed | 67 |
| 16 | ott | carrie | F | 13 | Lutheran | German | Ontario | No Occupation Listed | 230 |
| 4 | ott | catharine | F | 7 | Lutheran | German | Ontario | No Occupation Listed | 251 |
| 15 | ott | cena | F | 42 | Lutheran | German | Germany | No Occupation Listed | 230 |
| 5 | ott | charles | M | 5 | Lutheran | German | Ontario | No Occupation Listed | 251 |
| 3 | ott | christine | F | 29 | Lutheran | German | Germany | No Occupation Listed | 251 |
| 17 | ott | elizabeth | F | 7 | Lutheran | German | Ontario | No Occupation Listed | 230 |
| 6 | ott | elizabeth | F | 4 | Lutheran | German | Ontario | No Occupation Listed | 251 |
| 14 | ott | francis | M | 43 | Lutheran | German | Germany | Blacksmiths | 230 |
| 2 | ott | john | M | 30 | Lutheran | German | Germany | Coach, carriage, cart and wagon makers | 251 |
| 23 | owens | frank | M | 14 | Universalist | Blank | Ontario | No Occupation Listed | 255 |