City west of Sparks (4)
I believe the answer is:
reno
'city west of sparks' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for reno that I've seen before include "Nevada marriage and divorce centre" , "City in Nevada known for casinos and easy divorce" , "City in Nevada known for casinos and easy divorces" , "City in Nevada known for gambling and easy marriage/divorce" , "US divorce centre" .)