Arches National Park state (4)
I believe the answer is:
utah
'arches national park state' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for utah that I've seen before include "In USA, it's the Mormon state" , "The "Beehive" State, capital Salt Lake City" , "American state associated with Mormons and their faith" , "American state, capital Salt Lake City" , "US state N. of Arizona" .)