- Nutrition--Children2
- Orators.2
- Ortiz Rubio, Pascual, 1877-1963.2
- Owen, Ruth Bryan, 1885-1954.2
- Pan American Union Building (Washington, D.C.)2
- Parades--Washington (D.C.)2
- Passersby.2
- Pay equity2
- Payne, John Barton, 1855-1935.2
- People with disabilities.2
- Physicians.2
- Pittman, Key, 1872-1940.2
- Police--United States.2
- Political crimes and offenses--Investigation.2
- Political parties.2
- Politicians--Mexico.2
- Politics and Government--New Jersey.2
- Politics and culture--United States--History--20th century.2
- Portraits, Group2
- Postal service.2