Websites
USEFUL INFORMATION FOUND IN OTHER PLACES
Atlas of US Historical County Boundaries - Newberry Library
State Data - Select a state from the map to view all of the Atlas' content related to that state, including shapefiles, chronologies, and metadata.
Germany - Meyers Gazetteer with Maps
Online version with historical maps. A dictionary of place names describing provinces, states, counties, towns and villages [ Meyers Orts- und Verkehrs-Lexikon des Deutschen Reichs= Meyers Place- and Traffic directory of the German Empire]