A primary source is a firsthand account of an event that was created while the event was happening or at a later date by an eyewitness to the event.
A secondary source is a step removed from a primary source or firsthand account. It may be created using primary sources and often provides a synthesis or analysis of multiple sources of information.
Diaries, letters, memoirs, personal narratives
Historic photographs, images, or maps
Government documents (legislation, court decisions, letters, etc.)
Newspaper articles and political cartoons
Speeches
Artifacts
Audio or video recordings
Oral histories or interviews
Data or results of scientific studies
Encyclopedias
Text books
Reference books
Magazine and journal articles
Books that use primary sources to synthesize or analyze information
Source: Adams, Ansel, photographer. "Sumiko Shigematsu, foreman of power sewing machine girls, Manzanar Relocation Center, California." Photograph. From Library of Congress: Adams, Ansel, 1902- Manzanar War Relocation Center photographs. http://www.loc.gov/pictures/item/2002695109/ (accessed May 24, 2018).