Ochtrup - Ottobeuren
- Ochtrup (see Specials: Manuscript Census Westphalia)
St. Lamberti
- Oebisfelde (see Specials: Eastern FederalStates)
St. Katharinen Church Library
- Oelde (see Specials: Manuscript Census Westphalia)
St. Johannes
- Oldenburg
State Library
State Archives
- Olfen (see Specials: Manuscript Census Westphalia)
St. Vitus
- Osnabrück
Bishop's Archive
Bishop's General Vicariate
Diocesan Museum
Gymnasium Carolinum
Cultural History Museum
Parish Archive St. Johann
- Ostenfelde (see Specials: Manuscript Census Westphalia)
St. Margareta
- Ottenstein (see Specials: Manuscript Census Westphalia)
St. George
- Ottobeuren
Abbey
