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Primary Sources

What is a "Primary Source"?

Image of a yellowed letter written by Arthur C. Stockwell, a Union soldier from Indiana in the Civil War.

(Letter from Arthur C. Stockwell, the 137th Regiment of Indiana Volunteer Infantry, to his father John Stockwell. Source: Indiana Memory Hosted Source Collections.)

When your professor asks you to use "primary sources" in your research project or paper, they are asking for materials created at the time of the historical era or event you're studying, and that reflect the attitudes and experiences of those who witnessed these events first-hand. "Primary sources" can include speeches, letters, diaries, photographs, or any historical document that bears direct witness to historical events. 

In contrast to primary sources, "secondary sources" are secondhand accounts, analyses, etc., by historians, scholars, and researchers. These works often incorporate the use of primary sources, but are not considered primary sources on their own. (Fun fact: Your paper or project would also be an example of a secondary source!). 

Primary and Secondary Source Examples

Examples of Primary and Secondary Source Documents by Discipline


Primary Source

Page from U.S. Treasury brochure for the 4th war loan from 1944.

Secondary Source

Book published in 2016 that describes the history of spies, code breakers and covert operations during WWII. This is a secondary source because it uses and analyzes information from primary source documents.

Primary Source

Historical Newspaper articles can also count as primary sources because they represent original documents from a specific time period. Current day newspaper and magazine articles are typically considered secondary sources.

Lowell Daily Citizen (Lowell, MA, United States), Thursday, August 8, 1861, Vol. XI, Issue 1619.

From Nineteenth Century U.S. Newspapers

Secondary Source

Book published in 2008 that describes the massive number of deaths that occurred as a result of the civil war and the effect that this had on the nation.This is a secondary source because it uses and analyzes information from primary source documents.


Health Science

Primary Source

In the sciences, original research articles are also considered primary sources

Secondary Source

New York Times health blog article on ACL injuries.

This is a secondary source because it uses information gathered from original research articles