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- Audubon State Historic Site
- Auseklis Ozols
- Charles A. O’Niell
- Dave Oxley
- George Ohr
- Kid Ory
- Joseph “King” Oliver
- Lee Harvey Oswald
- Oak Alley Plantation
- Oaklawn Manor Plantation
- Oil and Gas Industry in Louisiana
- 8.12 f. Oil and Gas Industry in Louisiana
- Okra
- Old Arsenal Museum
- Old State Capitol
- 1.8 d. Old State Capitol
- Ollie Tucker Osborne
- Opelousas Massacre of 1868
- Opera and Ballet
- Orleans Theatre
- 7.14 f. Oscar Dunn
- Our Lady Queen of Heaven Church
- Ozeme Carriere
- Rachel O’Connor
- Rick Olivier
- William Christopher “W. C.” O’Hare
