Harry demonises US city (3,6)
I believe the answer is:
des moines
'us city' is the definition.
'Des Moines' can be an answer for 'city' (Des Moines is an example). I am not certain of the 'us' bit.
'harry demonises' is the wordplay.
'harry' is an anagram indicator (I've seen this in other clues).
'demonises' is an anagram of 'DES MOINES'.
Can you help me to learn more?
(Other definitions for des moines that I've seen before include "Iowa's capital? Yes" , "State capital of Iowa" , "city on the plains" , "Largest city of Iowa" , "capital city" .)