Not a regulated port in part of Canada (7)
I believe the answer is:
ontario
'part of canada' is the definition.
('Ontario' is part of 'canada')
'not a regulated port' is the wordplay.
'regulated' is an anagram indicator.
'port' becomes 'rio' (I've seen this before).
'not'+'a'='nota'
'nota' is an anagram of 'onta'.
'onta'+'rio'='ONTARIO'
'in' is the link.
(Other definitions for ontario that I've seen before include "part of Canada" , "city" , "Oration in Canadian province" , "Province of central Canada" , "vast lake" .)