I don't know what the professionals use to find places like Berne, but I
absolutely love the New York State Atlas & Gazeteer ("TOPO MAPS of the
ENTIRE STATE") put out by DeLorme Mapping for a little over $15 in book
stores. Actually they have about half of the country published this way.
It shows the names and boundaries of every township within every county,
as well as roads, hills, forests, etc. Of course the information in it is
modern (intended for hikers and hunters) so it doesn't help with the very
early counties and towns changing boundaries and whatnot, but it's 100%
better than your average road atlas!