Complete data in map and textual form, about the creation and all subsequent changes (dated to the day) in the size, shape, and location of every county in the fifty United States and the District of Columbia.
This historical map collection has over 22,000 maps and images online. The collection focuses on rare 18th and 19th century North American and South American maps and other cartographic materials. Historic maps of the World, Europe, Asia, and Africa are also represented. Offers ability to zoom.
The Harvard Map Collection is one of the oldest and largest collections of cartographic materials in the United States with over 500,000 items. However, only a representative sample of the collection has actually been imaged. Visit this site to find maps of the Revolutionary War, London, Massachusetts towns, and other "treasures."
This oddly named site is a highly idiosyncratic portal. The links are not as reliable as the Perry-Castaneda UT Austin site. However, it has links to an extensive number of sites and has a good subject list with links that are on no other portal. Beware of MIA's.
More than 5,000 maps representing many different time periods. Their user friendly license allows teachers and students to use up to 25 maps in non-commercial educational projects without further permission. You may need to right click and save the file in order to get it to open.
Digitized maps from Baylor University concerning the Civil War. The maps come from the Atlas to Accompany the Official Records of the Union and Confederate Armies, published in 1895. Searchable by keywords, including military personnel, city, state, and geographic features.