Finding Primary, Secondary, and Tertiary Sources

Primary sources, secondary sources, and tertiary sources are types of sources you will be asked to use in college research.  You most likely have already used all three without realizing it.  Understanding what they are, where to find them, and how to distinguish between them is an essential research skill. (ALA, 2000).  You can find these sources using library tools such as OneSearch, Library Databases, Research Guides, and authoritative websites such as the Census, U.S. Government Information, and Library of Congress, among others.

Primary sources are items that offer original, firsthand evidence on a subject you are researching, such as a letter written by someone during a war, a presidential speech, social media post, or oral history by someone who lived in the Bronx.  They were created or retrieved at the time of the event and have not been modified. (Seton Hall University Libraries, 2026)

Primary sources come in a variety of formats – some formal, like books, government documents, and peer-reviewed articles – and informal, like blogs, tweets, interviews, podcasts, and videos. (Association of College and Research Libraries, 2016).  Additional primary sources include advertisements, artifacts, cartoons, census data, clinical trials, clothing, court records, diaries, images, letters, maps, memoirs, newspapers, notated music, photographs, raw data, reports, speeches, and voter registration lists. (Library of Congress, n.d.).

Primary Source – Evidence of an Event, Data, Text | Where to Find

1. Presidential Speeches – Miller Center, American Presidency Project
2. Women and Social Movement Documents | Black Thought and Culture, Women and Social Movements in the U.S., Library of Congress
3. 1968 Olympics Black Power Salute photo | JSTOR, New York Times: Historical Newspapers, Smithsonian
4. ScienceStudy with new data | PubMed, Science Direct
5. Literary texts (e.g. Their Eyes Were Watching God) | OneSearch, Project Gutenberg
6. Census data | data.census.gov, IPUMS

Tip: When searching for primary resources, combine your topic with terms like “papers,” “records,” “documents,” “correspondence,” “diaries,” “speeches,” “narratives,” or “interviews.”

Secondary sources explain, analyze, or interpret primary sources.  Created after an event, they provide historical perspective and scholarly context.  Examples include biographies, documentaries, literary criticism, scholarly articles, and textbooks. (Texas A&M University-Corpus Christi Library, n.d.).

Secondary Source – Explains and Analyzes Primary Sources | Where to Find

1. American Presidency | JSTOR, Academic Search Complete
2. Women and Social Movement Articles | Literature Resource Center
3. Analysis of 1968 Olympics Protest | Ethnic Newswatch, Google Scholar
4. ScienceStudy | PubMed, Cochrane Library, Web of Science
5. Literary Review or Criticism | Gale Books and Authors, Gale Literature
6. Census Data | Social Explorer, Economic Indicators, Northeast Slavery Records Index

Tip:  When searching for secondary sources, combine your topic with keywords such as “analysis,” “interpretation,” “review,” or “history.”  Filter results within databases, by resource type (e.g., peer-reviewed journals, books) or “topic/subject.”

Tertiary sources abstract, compile, organize, or summarize information from primary and secondary sources and help build background knowledge before deeper research.  Examples include dictionaries, encyclopedias, fact books, handbooks, research guides, textbooks, timelines, and Wikipedia. (University of Minnesota, Crookston Library, n.d.).

Tertiary Source – Overview, summary, background, and where to find them in the databases

1. American Presidency, Movements, Events | Gale eBooks, Britannica | Encyclopedia of the American Presidency
2. Women’s Movement and Civil Rights | CQ Researcher, Oxford Reference Online | Encyclopedia of Women in American History
3. Analysis of 1968 Olympics Protest | CREDO | African American History
4. Scientific background | MedlinePlus, CDC, Merck Manual, Scopus
5. Literary Review, Criticism | Gale Literature, Scribner Writers Online | Masterplots. African American Literature
6. Census Reports | America Counts, Statistical Ab stract of the United States

Tip:  When searching for tertiary sources, combine your topic with keywords such as “encyclopedia,” “handbook,” “dictionary,” or “textbook.”

Combining all three source types strengthens your research and supports critical thinking by helping you evaluate, interpret, and compare their purposes – a helpful lifelong learning skill. (American Library Association, Association of College and Research Libraries [ACRL], 2018).

A research guide on Primary, Secondary, and Tertiary Sources is available at:

https://libguides.lehman.edu/Primary-Secondary-Tertiary-Sources

Rebecca Arzola

References

American Library Association, Association of College and Research Libraries. (2018).  Guidelines for primary source literacy. https://www.ala.org/sites/default/files/acrl/content/standards/Primary%20Source%20Literacy2018.pdf

American Library Association. (2000). Information literacy competency standards for higher education. https://alair.ala.org/server/api/core/bitstreams/ce62c38e-971a-4a98-a424-7c0d1fe94d34/content

Association of College & Research Libraries. (2016). Framework for information literacy for higher education. https://www.ala.org/acrl/standards/ilframework

Seton Hall University Libraries. Primary Sources – An Introductory Guide. Retrieved March 30, 2026, from https://library.shu.edu/primarysources

Texas A&M University-Corpus Christi Library. (n.d.). Secondary sources. https://guides.library.tamucc.edu/c.php?g=1371058&p=11046639

University of Minnesota, Crookston Library. (n.d.). Primary, secondary, and tertiary sources. Sources. Retrieved March 30, 2026, from https://crk.umn.edu/library/primary-secondary-and-tertiary-sources

Library of Congress. (n.d.). Primary sources. Library of Congress. https://guides.loc.gov/student-resources/primary-sources#s-lib-ctab-24530592-1