This is Midnight Hole, a beautiful swimming hole in Newport, NC, near the Tennessee border off of Highway 40. Click here for directions!
When I went in late July, there were TONS of butterflies.
The water is crystal clear and COLD
To get to the swimming hole, you hike in a little over a mile on a medium grade trail that is well maintained and wide enough for a vehicle to traverse. It's a bit of a walk but well worth it. Horses are also allowed.