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Primary, secondary and tertiary sources: Primary sources

Navigating the research process


A primary source is a document that dates from the time of a historical event.

Primary sources are your evidence for your argument. A relevant primary source will be closely connected to the event itself or to people who participated in the event. Here are a few examples:

  • a letter from someone who participated in the event
  • a newspaper article from the time of the event
  • a treaty between countries or opposing groups 
  • a law or statute
  • a diary entry
  • a political cartoon published in a newspaper
  • data (casualty reports, census data, polling data, population numbers - data can take many forms but should come from an authoritative source

A note about photographs as primary sources:

Photographs can be powerful primary sources but should be carefully selected to be sure they convey meaningful information. A photograph of nurses working on a US Civil War battlefield conveys more information than a formal photo of a Civil War nurse sitting in a chair.

What type of primary source is most useful?

Before you go searching for primary sources, think about what type of source will best support your argument. This will depend on your topic: if you are investigating the role of women in the US Civil War, you may look for diary entries and photos. If you are interested in advancements in medicine during the Civil War you will perhaps look for reports from armed services of the time, and publications in medical journals during and after the war.

Finding primary sources in Menlo School Library databases

Finding primary sources on the internet

Image collections

Citation checklist

Do you want to be sure you have formatted your research paper correctly? Click the link below to download a Chicago style citation and formatting checklinst.