The Civil War Preservation Trust has a wonderful page of assorted American Civil War maps. Includes the excellent CWPT topographical maps [viewable online, download .pdf requires free registration], and historical maps. My favorites are the animated maps, on the map of the First Day of Chancellorsville you can toggle between the topo map and a present-day satellite view so you can see the effects of modern development on the battlefield. [via]
posted by marxchivist on Jun 12, 2009 - 5 comments

Beijing in 1930. First mentioned on the blue back in 2001, the David Rumsey Historical Map Collection now has over 18,460 maps online—120 of them viewable as Google Maps overlays.
posted by Knappster on Aug 11, 2008 - 8 comments

Physicist Howard Wiseman has a hobby, history. On his website he has three history subsites, filled with lots of information: 1) Ruin and Conquest of Britain 2) 18 Centuries of Roman Empire 3) Twenty Centuries of "British" "Empires". Especially informative are his many maps. As he says himself: "Drawing historical maps of all sorts has been a hobby of mine since my mid teens. Now I can do it digitally, and inflict it upon the world!"
posted by Kattullus on Feb 19, 2008 - 18 comments

Online Historical Map Exhibits from the Smith Centre for Cartographic Education. Nice collection - take a look at the Columbus Letter, Portuguese America and the exhibit on diasporas.
posted by plep on Aug 12, 2004 - 3 comments

David Rumsey is putting his tremendous collection of historic maps online. Using technologies from Luna Imaging and LizardTech, he has so far made available high-resolution images of over 4000 of the 150,000 maps in his collection.
posted by Aaaugh! on Apr 13, 2001 - 5 comments