- Odone, Father Nicolo Carlo (1)
- Odutayo, Madeleine (1)
- Oestreicher, Samantha (University of Minnesota, Twin Cities) (2)
- Office of Supervising Engineer (2)
- Office of War Information (1)
- Office of the Supervising Engineer (22)
- Office of the Supervising Engineer, Physical Plant Department (1)
- Ogaard, Louis A. (1)
- Ogden, Darcy E. (Scripps Institution of Oceanography) (1)
- Ogden, William Augustine, 1841-1897. (2)
- Ogilby, John, 1600-1676 (8)
- Ogun, Bryan (1)
- Oh, Sang-Hyun (University of Minnesota, Twin Cities) (1)
- Oh, Sewoong (University of Illinois at Urbana-Champaign) (1)
- Ohage, J. (1)
- Ohio. State Commissioners of Public Printing (1)
- Ohno, Tsookoomou (1)
- Ohtsuki, Yukiyoshi (Tohoku University) (1)
- Okamoto, Ippō, active 1685-1733 (2)
- Okamoto, Ippō,active 1685-1733. (7)
