National Maps

National Map
Interactive map for the entire country with over a hundred layers of information.The National Map is a collaborative effort among the USGS and other Federal, State, and local partners to improve and deliver topographic information for the Nation.

National Atlas
A similar product with more emphasis on producing your own maps from many layers of information. Coverage of layers is national with less emphasis on local partners. Downloadable data sets.

Outline Maps

A much requested category. The Perry Casteneda site is an inclusive portal, but it can get tedious trying the different links to find what you need.

Outline Map Sites
From the Perry Castaneda portal
Interactive Ancient Mediterranean Map Room
Example of a specialized site with excellent outline maps of the Ancient world.

Web Portals

Oddens' Bookmarks
Massive portal with thousands of links to all thing cartographic.

Perry-Castañeda Library Map Collection
A portal to a wide variety of online maps.

Map History/History of Cartography
History of Cartography portal with many links.

Historic Map Collections

American Memory
The Library of Congress site with several large subject map collections, e.g., railroad maps, civil war maps.

David Rumsey Map Collection
20,000 historical maps. These can also be searched through Cornell's online catalog