In New York State there is no state-wide law against riding on the sidewalk. It is up to the various municipalities to make their own law. I just checked the jurisdiction I ride in the most and there is no ordinance about bikes on sidewalks, so I can ride on the sidewalk legally. That doesn't mean it is not stupid or dangerous though. It also doesn't mean that there are actually sidewalks to ride on to begin with.

There is one narrow bridge with a sidewalk and almost never has pedestrian traffic so knowing that biking the sidewalk there is a good thing although I think I would only do it if there are large trucks around and I'd go slow and get off if a pedestrian does appear.