Reside by the banks of Uncompahgre, bighorn roaming (9)
I believe the answer is:
neighbour
'reside' is the definition.
(neighbouring is a kind of residing)
'banks of uncompahgre bighorn roaming' is the wordplay.
'banks of' suggests removing the centre (the banks are the sides of the word).
'roaming' is an anagram indicator.
'uncompahgre' with its centre removed is 'ue'.
'ue'+'bighorn'='uebighorn'
'uebighorn' with letters rearranged gives 'NEIGHBOUR'.
'by the' is the link.
(Other definitions for neighbour that I've seen before include "Person alongside" , "One who must live alongside" , "lovable person?" , "One lives near you" , "Person who lives close by" .)