The Ulster & Delaware Railroad Historical Society is a chapter of the National Railway Historical Society (NRHS). It focuses on the history of the railroads and related social, economic, and cultural institutions of the Catskill and Hudson Valley regions. That history, which began with the charter of the Catskill & Ithaca Railroad in 1828, encompasses numerous proposed and built railroads and trolley lines within Ulster, Delaware, Greene, Schoharie, Albany and Otsego counties.