O'Bryen, Dennis [1 reference]

“Observator” [See redirect]

Odell, Jonathan [1 reference]

Ogden, John C. [1 reference]

Ogilvie, James [1 reference + 1 subentry]

Ogle, Benjamin [1 reference]

Ohio River [2 references]

Ohio Territory [1 subentry]

Orange County, Va. [5 references + 3 subentries]

Oswald, Eleazer [2 references + 1 “see also” entry]

Otis, Harrison Gray [9 references]

Otis, Sally Foster (Mrs. Harrison Gray) [1 reference]

Otis, Samuel A. [1 reference]

Ottoman Empire [1 reference]