Our list of libraries consist primarily of original historical documents, mostly, though not wholly, pertaining to American history and the study of American culture. Those of note will be so marked: !

For a modern look at the United States, go to the USGS National Map .

American Journeys: Eyewitness Accounts of Early American Exploration and Settlement
Along with its primary texts, the site offers over 100 historical and modern maps, charts and diagrams covering the entire United States. Search under 'images' for 'maps'. From the Wisconsin Historical Society.
The American Revolution and Its Era: Maps and Charts of North America and the West Indies 1750-1789
From the Library of Congress. (We only wish the Library would make these pages a bit more easy to use.)
American Civil War
Includes an extensive list of battle maps arranged by state and chronology.
American Civil War
From the Library of Congress.
Archives of the West
From PBS and WETA, the collection includes some maps among its images..
The Cartographic Creation of New England
A wealth of period maps and explanatory texts documenting the European encounter with New England from the Osher Map Library and Smith Center for Cartographic Education at the University of Southern Maine.
The Civil War Home Page
An excellent collection of documents critical to the war as well as a wealth of other features on its history.
! Cultural Maps
An extensive collection, plus a thorough directory of other map sites - from the University of Virginia.
Hargrett Rare Book and Manuscript Library
Its extensive map collection begins in the 16th century, and offers both foreign and domestic maps of the United States.
Heading West/Touring West
The New York Public Library offers two collections: the first a collection of maps documenting the development of the West, and the second, a collection of ephemera tracing the history of performing arts migrating westward. Both collections include explanatory essays.
Lewis and Clark: Maps of Exploration
A history of the mapping of North America, from the first to those used by the Lewis and Clark expedition.
! Library of Congress Maps Collection
All subjects from 1500 to the present.
Mapping History
Places maps in historical context with some explanatory text. From the University of Oregon.
! National Atlas
From the Department of the Interior, a wide variety of United States maps, including historical, many of which are printable.
New York Public Library Digital Gallery
Provides access to over 480,000 images digitized from primary sources and printed rarities in the collections of The New York Public Library, including illuminated manuscripts, historical maps, vintage posters, rare prints and photographs, illustrated books, printed ephemera, and more.
! Perry-Castañeda Library Map Collection
From the University of Texas, the Library offers maps of everywhere, but includes a significant collection of historical maps of the United States. This collection also includes some of the most detailed maps we have found.
United States Military Academy Atlases
From ancient warfare to Iraq and Afghanistan.
! David Rumsey Historical Map Collection
11,000 maps on line, mostly focused on 18th and 19th century America.