This is very cool! If you like history, this gives an idea of the shifting regional cultural divides throughout US history. It shows how some parts of the country voted in certain presidential elections, and regional support or opposition to many key congressional acts.
The DSL (Digital Scholarship Lab) at the University of Richmond has digitized and enhanced with 21st Century technologies the maps from the 1932 Atlas of the Historical Geography of the United States by Charles O. Paullin and edited by John K. Wright.
There is an intro video that explains what has been done with this atlas. Have fun.
Scanning and digitizing for this project was done by the Discovery, Technology & Publishing department at the University of Richmond’s Boatwright Memorial Library.