American Shores: Maps of the Middle Atlantic Regio - http://www.nypl.org/research/midatlantic
New York Public Library's collection of early colonial and U.S. maps, including roads and canals, harbors, and Revolution battle **In-library access may require use of Internet Explorer World Languages edition.**
Early Washington Maps: A Digital Collection - http://www.wsulibs.wsu.edu/holland/masc/xmaps.html
A collaboration of Washington State University and the University of Washington libraries: includes timeline searching, geographical browsing, a separate San Juan Island area collection, and impressive advanced browsing capability.
Historical Atlas of Europe - http://www.euratlas.com/summary.htm
Maps of Europe by century from 1 A.D. through 1700, showing political boundaries. Includes links to Roman battle maps and the Online Encyclopedia of Roman Emperors.
Historical Maps - Perry Castaneda Library - http://www.lib.utexas.edu/maps/historical/index.html
Includes maps of the world, countries and U.S. states, as well as historical maps of exploration, military battles, astronomy and more.
Lewis and Clark: The Maps of Explorations - http://www.lib.virginia.edu/speccol/exhibits/lewis_clark/index.html
Provides maps as well as historical commentary on the Lewis and Clark Expedition.
Oregon Trail Maps - http://www.endoftheoregontrail.org/maplibrary/oregontrail.html
Detailed maps from the Oregon Trail Interpretive Center.