Last monument in Arizona (9)
I believe the answer is:
tombstone
I believe this clue is a double definition.
'last monument' is the first definition.
(I've seen this before)
'in arizona' is the second definition.
(I've seen this before)
(Other definitions for tombstone that I've seen before include "Where to find epitaph" , "Graveyard marker" , "Does it display departure date" , "film location" , "Memorial in churchyard - town in Arizona" .)