- Oakes, Rebekah.1
- Oberholser, Harry C. (Harry Church), 1870-1963.1
- Odell, Mrs. W. H.1
- Odland, T. E. (Theodore Eugene), 1892-7
- Office of Economic Opportunity. Mid-Atlantic Region.1
- Ogden, H. C.6
- Ogle, Alice M.1
- Oglebay Institute (Wheeling, W. Va.)9
- Oglebay Institute (Wheeling, W. Va.). Mansion Museum.3
- Oglebay Park (Wheeling, W. Va.)4
- Oglebay Park Saddle Club (Wheeling, W. Va.)1
- Oglebay, Crispin.2
- Ohio Arts Council.1
- Ohio County (W. Va.). Board of Education.1
- Ohio County Medical Society (Wheeling, W. Va.)2
- Ohio County Public Library (Wheeling, W. Va.)1
- Ohio Folklore Society.1
- Ohio Genealogical Society.1
- Ohio Historical Society.20
- Ohio Power Company.1
