Janus, an organised city in a USA territory (3,4)
I believe the answer is:
san juan
'city in a usa territory' is the definition.
'San Juan' can be an answer for 'territory' (San Juan is an example). I am unsure of the 'city in a usa' bit.
'janus an organised' is the wordplay.
'organised' is an anagram indicator.
'janus'+'an'='janusan'
'janusan' with letters rearranged gives 'SAN JUAN'.
Can you help me to learn more?
(Other definitions for san juan that I've seen before include "Hispanic capital" , "Capital of Puerto Rico" .)