Definition: A primary source is a source that you cite in your writing that is as close to possible as the original information. A primary source is the most direct place you can find the information you want to write about. For example, Census.gov would be a primary source for a population estimate of your city, whereas a newspaper article detailing the number would not be considered primary. Some other examples of primary sources are peer reviewed research publications, journals, diaries, legal documents, government records, original maps, photographs, original manuscripts, institutional records, or national archives.
In citing the Hispanic population in the city, we used the 2000 census numbers as a primary source.