The quest for primary sources can often start from reading a good academic book on your topic. In addition to the sources listed below, you may find others of interest by checking the footnotes, endnotes and bibliography of a published secondary source.
Start with a keyword search in the Catalog. If you find something that looks useful, look at the detailed view of the catalog record and try to identify the "subject" assigned. For many topics, there's an official term used in all library catalogs, like:
Then, do the Subject search with the authorized Subject heading. You may wish to include one of these words as a keyword or a subject:
To find works published in a particular time and place, explore the search options. It is usually possible to limit your search by date, language, or location of publication.
Please also explore the shelves in the African American Studies Reading Room, which has a number of compilations of primary source documents. Some examples include:
Princeton University Library has a number of collections of manuscripts that reflect African American history. You may search the list of Finding Aids at https://findingaids.princeton.edu/.
Some collections of note include: