Irishman, in the past, in a strange part of South America (9)
I believe the answer is:
patagonia
'part of south america' is the definition.
(I know this)
'irishman in the past in a strange' is the wordplay.
'irishman' becomes 'Pat' (Patrick is a common Irish name).
'in the past' becomes 'ago' (synonyms).
'strange' is an anagram indicator.
'in'+'a'='ina'
'ina' anagrammed gives 'nia'.
'pat'+'ago'+'nia'='PATAGONIA'
(Other definitions for patagonia that I've seen before include "Region of South America" , "part of South America" , "Region of southern Argentina and Chile" , "South American region" , "Southernmost region of S America" .)