1. Check the Encyclopedia of New York State, Olin Library Reference, F119 .E53 2005 ++
  2. Search the catalog for the county as a subject. e.g., Tioga County (N.Y)  In the drop-down menu, select Subject Browse. Scroll through the subject-headings. Keep in mind that county histories might also discuss the towns within the county.
  3. Search the catalog for historical county atlases and directories
  • ____ County (N.Y.) > Maps; 
  • ____ County (N.Y.) > Directories; 
  • Real property > New York (State) > ___ County > Maps

Finally, you might also contact/visit local history centers