AfriGeneas States Research Forum
[Nationwide] MAP GUIDE to the U.S. Federal Censuses
MAP GUIDE to the U.S. Federal Censuses, 1790-1920
Throughout U.S. history, county boundaries changed from one decennial census to the next, especially before 1900. The best way to know if you're looking in the right county as you crank or scroll through the census is to consult the MAP GUIDE by William Thorndale and William Dollarhide. State by state, this highly acclaimed reference work maps out county boundaries for every federal census from 1790 through 1920 and superimposes modern county boundaries overtop of them.
Don't be lost in the census without it!