Alongside traditional textbooks, these subject headings will provide similar materials designed for teaching skills and conceptswithin various subject areas.
"The American Yawp offers a free and online, collaboratively built, open American history textbook designed for college-level history courses." While not strictly K-12, this content could be adapted (especially to the AED level).
"The mission of Independence Hall Association, owner of ushistory.org, is to provide a forum for learning and discussing American history and values. Toward that end we offer these three courses written by a former Pennsylvania history teacher of the year as well as other historians as a resource to our visitors."
"Connecting the dots of history—people, places, and events—into coherent narratives that help students make sense of, and prepare for, the world they live in today." An Open Educational Resource.
