Here are a number of interactive maps on ancient European history (the fall of Rome is excellent) and North American history. This is from the University of Oregon.
Growth of contiguous USA: www.ac.wwu.edu/~stephan/48states.html
This is a small but complete animation of the geographic growth of the continental United States. Ed Stephan's site is an interesting use of the internet to self-publish original research outside the mainstream of academia.
America from 34,000 BC to 2000 AD: http://www.boltmap.com
This animated map of the US area of North America is accompanied by a timeline with epochal events from 43,000 BC to 2000 AD. It puts in perspective the early native American migrations, Spanish conquests, colonial period including the numerous wars, and the growth of the United States. Roll over features for names. A red dot in the timeline moves with the history, and it can be moved to any date. More detailed events are headlined in the appropriate year. It can be played and paused, and go forward or backward one year. The geographic shapes are schematic and there are some obvious bloopers, but it is very valuable for placing the entire geographic history of America in perspective.
Westpoint provides these military maps on wars involving the United States. These are the most detailed and accurate maps available; from Westpoint books available in libraries which have facing text.Index of historic maps: http://users.erols.com/mwhite28/maplinks.htm
This site provides an outline of geographic areas and historic periods, with links to maps on the web.
This page provides a list of the states, and location. Select a state for a brief introduction to it.
Sections of U.S. history have links to primary sources in the Library of Congress.U.S. chronology of documents: http://www.yale.edu/lawweb/avalon/chrono.htm
This major resource provides listings of major and minor documents in U.S. history, from the 17th century to the present. Select a document to go to it. From the Avalon collection at Yale.
This site from the University of Groningen in the Netherlands has numerous articles, general histories, presidential materials, biographies, and links.American Memory Project: http://lcweb2.loc.gov/ammem/ammemhome.html
This site from the Library of Congress has great research materials in an incredible range of collections. The introductory essays are invaluable.American Civil War: http://www.factasy.com/civil_war/index.shtml
Comprehensive American Civil War site with forums.
This is the official White House listing of U.S. Presidents, with portraits and brief biographies.Essentials of U.S. Presidents: http://www.ipl.org/div/potus/
This is an excellant site for basic information on all the presidents, including the electoral vote, cabinets, internet biograpies and internet sources.Essentials of U.S. Presidents: http://odur.let.rug.nl/~usa/P/index.htm
This site from the University of Groningen in the Netherlands has extensive material on all the American Presidents.
This is a terrific gateway to web sites on American history for all students. It is visually delightful and very well organized.Virtual Library for history: http://vlib.iue.it/USA/index.html
This site provides access to many reference websites. "The best single gateway for history resources on the net." --Houghton-MifflinHotlist of U.S. history websites http://sln.fi.edu/tfi/hotlists/government.html
This site from the Franklin Institute Online lists hot websites for U.S. History.American studies links: http://myweb.uiowa.edu/rhorwitz/
This is an excellant and usable arrangement of materials related to American history.