Well, I'm claiming victory on UI 55. This is a section of the Youghiogheny River in southwestern Pennsylvania, which is referred to locally as "the loop", for obvious reasons. This is one of the most popular whitewater boating rivers in the northeast, and the run here begins just below the falls at Ohiopyle and then proceeds seven or eight miles downstream. Alternatively, boaters can park in Ohiopyle and do just "the Loop", taking their boats back out at the far end of the Loop and hiking back up to their cars. Fun wow!
And I have no guesses for UI 58, either, so time for hints. This site was a movie location. If you were to approach the fictional locale filmed here, you should not expect a warm welcome.
With that, we come to the newest installment:
Where are we? Rot-13 your guesses, folks!