The closest “real” ski areas to Sullivan County are Belleayre in the northern Catskills, about 44 miles from Roscoe (1 hour driving) and Elk Mountain in Pennsylvania. Elk is a mountain with a 1,000 vertical and is 31 miles west of Callicoon, about a 45 minute drive.
There are many closer ski hills, that are smaller in size. Mt. Peter in Warwick, New York is celebrating its 80th season with 12 different runs. Big Bear at Masthope Mountain in Lackawaxen, Pennsylvania, is just across the Delaware River from Barryville. Big Bear is a smaller mountain, good for an occasional day or to try out those new skis. And in Sullivan County itself, we have Holiday Mountain near Bridgeville with a 400 foot vertical and the Villa Roma Ski Area near Jeffersonville with a 250 ft. vertical.