The digital edition of all of the nearly 700 maps published in the 1932 version of Atlas of the Historical Geography of the United States by Charles O. Paullin & John K. Wright contains maps that "are enhanced here in ways impossible in print, animated to show change over time or made clickable to view the underlying data—remarkable maps produced eight decades ago with the functionality of the twenty-first century."
Atlas of the Historical Geography of the US
Atlas of the Historical Geography of the US