Geographic Names Information System
Contains information about ca. 2 million physical and cultural geographic features in the United States. Database can be searched by feature and will list the U.S.G.S. 7.5 minute topographic maps on which the feature is shown.

Live Ships Map
Provides real-time information about ship movements and ports, mainly across the coast-lines of Europe and North America using data collected by the Automatic Identification System (AIS).

Map Collection
The most extensive collection of maps on the web.  Developed and maintained by the Perry-Castaneda Library at the University of Texas.

MapMachine by National Geographic
Dynamic maps of the world.

MapQuest
Driving directions, maps, travel guides

National Atlas of the United States