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U.S. History - OpenStax
U.S. History - Open Textbook Library - Center for Open Education
The American Yawp
American History Online Textbook - Students of History
U.S. History by OpenStax (Official Print Version, hardcover, full color)
Free Online Textbooks - US History
Index - U.S. History - OpenStax
Building the American Republic -- a free digital textbook for US history
U.S. History – Open Textbook - UH Pressbooks
Amazon.com: United States History Textbook