Residents of Arnprior, Village — Sub-district M, surnames O (1881 Census)
| # | Surname | Given | Sex | Age | Religion | Origin | Birthplace | Occupation | HH |
| 11 | oakden | john | M | 40 | Anglican | English | England | Labourers nfs | 312 |
| 13 | obrien | catharine | F | 54 | Roman Catholic | Irish | Ireland | No Occupation Listed | 233 |
| 14 | obrien | catharine | F | 21 | Roman Catholic | Irish | Ontario | No Occupation Listed | 233 |
| 12 | obrien | james | M | 55 | Roman Catholic | Irish | Ireland | Labourers nfs | 233 |
| 17 | obrien | martin | M | 15 | Roman Catholic | Irish | Ontario | Labourers nfs | 233 |
| 16 | obrien | michael | M | 17 | Roman Catholic | Irish | Ontario | Labourers nfs | 233 |
| 15 | obrien | timothy | M | 19 | Roman Catholic | Irish | Ontario | Labourers nfs | 233 |
| 3 | oconnor | bridget | F | 4 | Roman Catholic | Irish | Ontario | No Occupation Listed | 174 |
| 22 | oconnor | catherine | F | 32 | Roman Catholic | Irish | Ontario | No Occupation Listed | 174 |
| 21 | oconnor | charles | M | 34 | Roman Catholic | Irish | Ireland | Boot and shoemakers and repairers | 174 |
| 24 | oconnor | charles | M | 13 | Roman Catholic | Irish | Ontario | No Occupation Listed | 174 |
| 1 | oconnor | john | M | 9 | Roman Catholic | Irish | Ontario | No Occupation Listed | 174 |
| 25 | oconnor | marya | F | 11 | Roman Catholic | Irish | Ontario | No Occupation Listed | 174 |
| 2 | oconnor | robert | M | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 174 |
| 23 | oconnor | timothy | M | 15 | Roman Catholic | Irish | Ontario | No Occupation Listed | 174 |
| 23 | odonnell | bridget | F | 35 | Roman Catholic | Irish | Ontario | Teachers (unspecified) | 199 |
| 13 | ogden | anne | F | 45 | Presbyterian | Irish | Ireland | Boarding and Lodging House Keepers and managers | 88 |
| 14 | ogden | william | M | 14 | Presbyterian | English | Ontario | No Occupation Listed | 88 |
| 9 | okeefe | ellen | F | 35 | Roman Catholic | Irish | Ontario | No Occupation Listed | 317 |
| 12 | okeefe | james | M | 4 | Roman Catholic | Irish | Ontario | No Occupation Listed | 317 |
| 11 | okeefe | mary | F | 6 | Roman Catholic | Irish | Ontario | No Occupation Listed | 317 |
| 8 | okeefe | michael | M | 40 | Roman Catholic | Irish | Ireland | Labourers nfs | 317 |
| 10 | okeefe | sarah | F | 8 | Roman Catholic | Irish | Ontario | No Occupation Listed | 317 |
| 13 | okeefe | timothy | M | 1 | Roman Catholic | Irish | Ontario | No Occupation Listed | 317 |
| 25 | oleson | stephen | M | 30 | Anglican | Swedish | Sweden | Mason nfs or combined | 320 |
| 21 | oliver | ada | F | 32 | Roman Catholic | French | United States | No Occupation Listed | 89 |
| 22 | oliver | arthur | M | 8 | Roman Catholic | French | Ontario | No Occupation Listed | 89 |
| 24 | oliver | elma | F | 4 | Roman Catholic | French | Ontario | No Occupation Listed | 89 |
| 20 | oliver | prosper | M | 38 | Roman Catholic | French | Ontario | Millwrights | 89 |
| 23 | oliver | rudolph | M | 6 | Roman Catholic | French | Ontario | No Occupation Listed | 89 |
| 3 | olleson | janet | F | 4 | Presbyterian | Swedish | Ontario | No Occupation Listed | 320 |
| 1 | olleson | jessie | F | 26 | Presbyterian | Scottish | Ontario | No Occupation Listed | 320 |
| 2 | olleson | martha | F | 9 | Presbyterian | Swedish | Ontario | No Occupation Listed | 320 |
| 17 | oreilly | owen | M | 28 | Roman Catholic | Irish | Ireland | Superintendents and managers, nfs | 255 |
| 23 | oriely | minnie | F | 23 | Roman Catholic | Irish | Ireland | Tailors and tailoresses | 148 |
| 8 | otterson | mary | F | 26 | Roman Catholic | Irish | Ontario | No Occupation Listed | 40 |