Here, I leave some links that might helo you to found information you need form the US History :) hope they are useful!
- http://www.ushistory.org/
- http://www.history.com/topics/american-history
- http://americanhistory.about.com/
- http://www.digitalhistory.uh.edu/
- http://www.youtube.com/playlist?list=PL8dPuuaLjXtMwmepBjTSG593eG7ObzO7s
Hope it works :D