The Catskills are known for their giant waterfalls.
You can find most of them on http://www.cnyhiking.com/CatskillWaterfalls.htm – but my favorite part about Ulster County is finding the hidden falls! Driving to Peekamoose mountain, one of the high peaks in the region, you pass about 6 roadside cascades. Some are on private property, but most you can park on the side of the road and hike up.
Here’s some pictures of my recent adventure with my partner in crime: