Encyclopedias, Almanacs, Transcripts, and Maps
- O Deus ego amo Te
- O Filii et Filiae
- O Roma Nobilis
- O'Boyle, Patrick A.
- O'Brien, Matthew Anthony
- O'Brien, Terence Albert
- O'Brien, Thomas C.
- O'Brien, William Vincent
- O'Callaghan, Jeremiah
- O'Clery, Michael
- O'Connell, Anthony, Sister
- O'Connell, Denis Joseph
- O'Connell, John Patrick
- O'Connell, William Henry
- O'Connor, Martin John
- O'Connor, Mary Flannery
- O'Connor, Michael
- O'Connor, Thomas Francis
- O'Cullenan, Gelasius (Glaisne)
- O'Daly, Daniel