library of congress historical map collection on line
http://www.maphistory.info/index.html -- nautical historical charts, U.S.
David Rumsey Historical Map Collection, a superb site, concentrating on American history (Exploration of Canada, Mexico, and the United States).
University of Georgia, and, logically, is mostly about Georgia.
the early cartography of Arizona and Sonora, at the University of Arizona.
the history of cartography -- comments and information -- no maps there, but plenty of links to such sites. Looks like a good "map-bibliography" type resource,
for those of you who want more than the pitifully few map links offered here....
www.topozone.com for topographic maps of the U.S.
http://www.maps-of-mexico.com/baja-california-norte-mexico/baja-california-norte-state-mexico-map-main.shtml -- maps of the state of Baja California (with access to all of Mexico).
The Gateway to Astronaut Photography of Earth -- Clickable Map Search -- Access to all photographs since 1961, get lists within 2.5 x 2.5 degree blocks. For space photos of Baja and all the Earth.
aerial views http://terraserver.microsoft.com/
National Oceanographic and Atmospheric Administration gateway to many historical charts....
Shuttle Radar Topography Mission - images of California.