It’s unfortunate king goes to a part of America (6)
I believe the answer is:
alaska
'part of america' is the definition.
(US state)
'it's unfortunate king goes to a' is the wordplay.
'it's unfortunate' becomes 'alas' (expression of regret).
'king' becomes 'K' (abbreviation for king in chess).
'goes to' means one lot of letters go next to another.
'alas'+'k'+'a'='ALASKA'
(Other definitions for alaska that I've seen before include "North-western US state" , "Most northerly US state" , "Northmost US state" , "that may be baked? Not by the sun" , "NW US state" .)