John Henry Oneil to Elizabeth Opic - 1911 Census household returns
- John Henry Oneil to William Henry Oneil
- James Oneil Jun to E W Oneill
- Edward Oneill to James Oneill
- James Oneill to John Oneill
- John Oneill to Matthew Oneill
- Matthias Oneill to Thomas Oneill
- Thomas Oneill to Angelo Onesti
- Davis Onetzky to John Ong
- John Ong to Christopher Ongley
- Chisholm Ongley to Percy Ongley
- Percy William Ongley to William Oniel
- Harry Onield to Charles Onion
- Charles Henry Onion to Isaac Henry Onion
- J Onion to Thomas Onion
- Thomas Onion to Albert Onions
- Albert Onions to Arthur James Onions
- Arthur William Onions to Edward Onions
- Edward Onions to Frederick Onions
- Frederick Onions to Henrietta Onions
- Henry Onions to James Onions
- James Onions to John Onions
- John Onions to John William Onions
- Joseph Onions to Martha Onions
- Martha Onions to Samuel Charles Onions
- Samuel David Onions to Thomas Watson Onions
- Thomas William Onions to William Alfred Onions
- William F Onions to Charles Ernest Onley
- Charles Fredrick Onley to Thomas James Onley
- Walter Onley to Morris Onnie
- Henry Walter Onnin to Cranley Charlton Onslow
- Daniel Onslow to James Onslow
- Jemima Onslow to William Onslow
- William Onslow to George Onyett
- Harry Onyett to William Onyon
- Thomas Onyons to Abraham Openshaw
- Agnes Openshaw to Daniel Openshaw
- Daniel Openshaw to Florence Openshaw
- Florence Josephine Openshaw to Henry Openshaw
- Henry Openshaw to James Openshaw
- James Albert Openshaw to John Openshaw
- John Openshaw to Joseph Openshaw
- Joseph A Openshaw to Robert Openshaw
- Robert Henry Openshaw to Thomas Openshaw
- Thomas Openshaw to William Openshaw
- William Openshaw to Elizabeth Opic