A run round US city (4)
I believe the answer is:
reno
'us city' is the definition.
(city in Nevada)
'a run round' is the wordplay.
'a' becomes 'one'.
'run' becomes 'r' (cricket abbreviation).
'round' says the letters should be written in reverse.
'one'+'r'='oner'
'oner' written backwards gives 'RENO'.
(Other definitions for reno that I've seen before include "Divorce capital of Nevada" , "Nevadan city" , "US gambling resort" , "City in Nevada known for casinos and easy divorces" , "City in Nevada noted for quickie divorces" .)