A distraught mate held in unfinished prison camp in part of America (9)
I believe the answer is:
guatemala
'part of america' is the definition.
('Guatemala' is part of 'america')
'a distraught mate held in unfinished prison camp' is the wordplay.
'distraught' is an anagram indicator.
'held in' means one lot of letters goes inside another.
'unfinished' means to remove the last letter.
'prison camp' becomes 'gulag' (gulag is a kind of prison camp).
'mate' anagrammed gives 'tema'.
'a'+'tema'='atema'
'gulag' with its final letter taken off is 'gula'.
'atema' going within 'gula' is 'GUATEMALA'.
'in' is the link.
(Other definitions for guatemala that I've seen before include "Central American country" , "country south of the USA" , "Republic in Central America" , "Central American state" , "Latin American place" .)