Primary Sources

American Memory Collections http://memory.loc.gov/ammem/ This collection from the Library of Congress includes free and open access to written and spoken words, sound recordings, still and moving images, prints, maps, and sheet music that document the American experience.
The Authentic History Center http://www.authentichistory.com/ An archive of images of artifacts and historic sounds from American popular culture operated by Michael Barnes, a high school history teacher.
Calisphere: A World of Primary Sources http://www.calisphere.universityofcalifornia.edu/ The website for the University of California's free gateway to primary sources.
Primary Documents in American History http://www.loc.gov/rr/program/bib/ourdocs/PrimDocsHome.html Collection from the Library of Congress that features links to primary documents (print and images) on the American Revolution 1763 – 1877, on the National Expansion and Reform 1815 - 1860, and the Civil War and Reconstruction 1860 - 1877.
Repositories of Primary Sources http://www.uidaho.edu/special-collections/Other.Repositories.html A listing of over 5000 websites describing holdings of manuscripts, archives, rare books, historical photographs, and other primary sources for the research scholar. Websites are arranged geographically.
Using Primary Sources on the Web http://www.lib.washington.edu/subject/History/RUSA/ Using and evaluating primary sources on the Internet.