US History Site provides US History teachers with a good collection of lesson plans, timelines, and images for teaching US History. Teachers will find materials appropriate for use in elementary, middle, and high school classrooms. To make finding resources easy, US History Site has organized all of their resources by eras and topics which you can browse through. You can also search for US History lesson plans through the general search box at the top of US History Site.
Here are some related resources that may be of interest to you:
The Library of Congress on YouTube
History Channel’s Guide to the US States
Shmoop Study Guides for History and Literature
Exploring US History Through Images and Documents
History Links You Might Have Missed