- American Prison Newspapers from JSTOR includes covers newspapers created within the U.S. prison system from 1800-2020. Most of the included material is open-access. More information on the collection is available at JSTOR Daily.
- Black Freedom from ProQuest centers on African American experiences and histories beginning in the 1700s and continuing through the present. All material is open-source.
- Digital Collections of the Harry Ransom Center, University of Texas Austen
- Digital Collections, Smithsonian Libraries
- Digital Collections at the University of Chicago
- Digital Newberry (the Newberry Library's digital collections)
- Enslaved: Peoples of the Historical Slave Trade includes primary source documents from the early 16th century onward, and continues to evolve and grow as more material is added.
- Google Arts & Culture
- Harvard Library Collections: Includes a range of open-access digital collections
- HathiTrust: Contains scanned books, pamphlets, and other documents from a variety of eras and regions and in a variety of languages.
- Internet Archive: Contains scanned books, pamphlets, audiovisual materials, and other documents from a variety of eras and regions and in a variety of languages. Houses the Wayback Machine as well.
- Last Seen: Finding Family After Slavery is an open-access collection of newspaper ads placed in hopes of finding family separated by the slave trade. Ads begin before the Civil War and continue into the early 1900s, and transcription is ongoing.
- Library of Congress
- National Archives, United States of America
- NYPL Digital Collections includes a variety of primary source materials from the United States and abroad, ranging from 18th century letters to 20th century fashion plates and beyond.
- Project Gutenberg: Contains scanned books, short stories, and other printed material, from a variety of eras and regions and in a variety of languages. Includes some audio books as well as texts of all new books entering the public domain.
- U.S. Colonial Laws from Bowling Green State University Library
These are all databases—you'll need to log in with your SXU credentials—and all contain primary source documents pertaining largely to the United States.
- African American History Serials covers material from the African American community from the 1830s through the mid-1900s and includes everything from social organizations and school registers to church documents.
- American Antiquarian Society Historical Periodicals covers material from the late 1600s through the early 1900s, and includes everything from maps, recipes, and jokes to newspaper, journal, and magazine articles.
- Arte Público Hispanic Historical Collection includes a wide range of material, from broadsheets, newspapers, and letters to literature, speeches, yearbooks, and beyond.
- Chicago Tribune Historical Files includes articles from 1849-1984
- HarpWeek: Articles, images, and more from Harper's Weekly, 1857-1912.
- New York Times Historical Files includes articles from 1851-2010.