| Artist | Titles | 1.
| Orloff, Gregory, 1890-1981, painter. | 3 | 2.
| Orlon, J. R., painter. | 2 | 3.
| Orlowsky, Lillian, 1914-2007, painter. | 1 | 4.
| Orman, Charles, painter. | 1 | 5.
| Orme, Daniel, painter. | 1 | 6.
| Orme, John, b. ca. 1830, painter. | 1 | 7.
| Ormsby, Dorothy, painter. | 1 | 8.
| Ornamental Iron Works, founder. | 1 | 9.
| Orndorf, painter. | 1 | 10.
| Orndorff, Martha Moran Sedgwick, 1842-1942, painter. | 1 |
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