MAPS

Lehigh was formed from Northampton 6 March 1812

Ed McClelland :Northampton 1874 files are in alphabetical order and suffixed with the Atlas page. The page doesn't show in the index--just in the file name.
http://www.usgwarchives.net/maps/pa/county/northamp/1874/

Chronology of all the PA counties

http://www.buckscountyhistory.com/chronological.htm

Interactive Pennsylvania County Maps

http://www.pagenweb.org/map/index.html

An excellent site to use to follow the formation of Pennsylvania Counties by year can be found at:

http://www.mypennsylvaniagenealogy.com/pa_maps.htm

Janie has now finished all 50 states for the 1914 state maps by County.
Alaska and Hawaii were not states, but she added them anyway. http://freepages.genealogy.rootsweb.com/~shastaca/maps_index.html