A very pretty waterfall is found on Ely Creek, a tributary to Jones Hole Creek, which is a tributary to the Green River in Dinosaur National Monument, in NE Utah.
There is also very interesting Native American Rock art along the stream near the waterfall. See more rock art photos here.
From Jones Hole Federal Fish Hatchery a well-marked trail follows the stream all of the way to its confluence with the Green River. The stream's water is clear and cold and supports a thriving population of brown trout. The waterfall is on a tributary and an obvious sign marks the way.
This scenic area is far off the beaten path. You don't stumble upon this place. You get there only if you make it a destination. It is a beautiful area well worth the trip.
Jones Hole Fish Hatchery: Lat: 40.587087, Long: -109.057511