Margaret O'donnell to Elizabeth O'neall - 1881 Census household returns
- Margaret O'donnell to Michael O'donnell
- Michael O'donnell to Patrick O'donnell
- Patrick O'donnell to Thomas O'donnell
- Thomas O'donnell to Joseph O'donoghue
- Joseph O'donoghue to Mary O'dorral
- Patrick O'dougharty to Bernard O'farrell
- Betsy O'farrell to Frances O'flaherty
- Francis O'flaherty to Jane O'garra
- Michael O'garra to James O'grady
- James Henry O'grady to Arthur O'hagan
- Bernard O'hagan to James O'hair
- James O'hair to Michael O'halloran
- Patrick O'halloran to Alex O'hara
- Alexander O'hara to Charles O'hara
- Charles O'hara to Felix O'hara
- Francis O'hara to James O'hara
- James O'hara to John O'hara
- John O'hara to Joseph O'hara
- Joseph O'hara to Michael O'hara
- Michael O'hara to Patrick O'hara
- Peter O'hara to Thomas O'hara
- Thomas O'hara to Anne O'hare
- Arthur O'hare to James O'hare
- James O'hare to Margaret O'hare
- Margaret O'hare to Thomas O'hare
- Thomas O'hare to Mark O'harra
- Martin O'harra to Daniel O'hearn
- Daniel A O'hearn to Michael O'kane
- Patrick O'kane to Margaret O'keefe
- Martin O'keefe to Patrick O'keeffe
- Patrick O'keeffe to Arthur O'leary
- Arthur O'leary to Jeremiah O'leary
- Jeremiah O'leary to Michael O'leary
- Michael O'leary to Joseph O'loughlin
- Patrick O'loughlin to John O'malley
- John O'malley to Maurice O'mally
- Michael O'mally to Thomas S O'may
- William O'may to Julia O'murney
- Elizabeth O'nail to John O'neal
- Margaret O'neal to Elizabeth O'neall