The New York State Library as well as other large research libraries, notably
the Map Division at the NY Public Library, SUNY Stony Brook, and some others
have historical maps of NYS. There were several commercial companies that
made maps of the state from the turn of the 19th c. forward and by
mid-century, you should be able to find maps published of the state in nearly
every year. Some of the map makers were David H. Burr, Augustus Mitchell,
Tanner, and others and later in the century, the Beers company, Colton, and
others made many atlases and maps of the state and parts thereof. You may
find some maps of NYS listed on the NYS Library's online catalog, Excelsior.

Good luck in your search.

Jim Corsaro