These collections bring together millions of items ranging from manuscript material to photographs, from books to film. The collections are strongest in pre-1925 material due to copyright considerations.
LOC: Library of Congress Digital Collections
Historic photographs, presidential papers, and more from the Library of Congress (migrated from the American Memory project)
DPLA: Digital Public Library of America
Over 20 million images, texts, videos, and sounds from "America’s libraries, archives, museums, and other cultural heritage institutions."
NYPL: NYPL Digital Library
More than 800,000 historical photographs, posters, maps, and other images from the collections of the New York Public Library