16th-20th Century Maps of Africa
The British Library's Magnificent Maps
David Rumsey Map Collection: includes over 35,000 maps, atlases, and charts from all over the world, although the main focus is North and South America of the 18th and 19th centuries.
Library of Congress Map Collection
NationalAtlas.gov : contains U.S. maps and data on boundaries, population, water, history, the environment, and more.
The Perry Castaneda Map Collection: includes links to maps and other map sites.
United Nations Cartographic Section: includes current locations of United Nations peacekeeping forces.