INTERACTIVE HISTORICAL MAPS OF ARKANSAS.
http://alabamamaps.ua.edu/historicalmaps/arkansas/
MISSOURI RAILROADS.
http://tacnet.missouri.org/~mgood/histo ... cmorr.html
RAILROAD HISTORY DATA BASE.
http://www.rrhistorical.com/rrdata/
THE FRONTIER COAST.
http://www.lib.noaa.gov/edocs/BACHE6.htm