Part of Canada - and parts of Iran too! (7)
I believe the answer is:
'part of canada' is the definition.
(I know this)
'parts of iran too' is the wordplay.
'parts of' indicates an anagram.
'irantoo' is an anagram of 'ONTARIO'.
'and' acts as a link.
(Other definitions for ontario that I've seen before include "Most easterly Great Lake" , "one of the provinces" , "Most populous Canadian province" , "city" , "A North American lake" .)