Timeline and Narrated Geographical History of the US
I don't normally like to promote something that costs money, but this site has two great free maps. The first has a scrolling timeline which breaks US history into states, territories, presidents, society, Native American, world, science and culture. The second item is a narrated map which describes the major changes to the US. It also has smaller maps popping up to better explain the narration. You can also go to just one era if that is more desirable.