Discovered in fresh ground in North America (12)
I believe the answer is:
newfoundland
'in north america' is the definition.
('Newfoundland' is part of 'north america')
'discovered in fresh ground' is the wordplay.
'discovered' becomes 'found' (to discover is to find).
'in' is an insertion indicator.
'fresh' becomes 'new' (synonyms).
'ground' becomes 'land' (synonyms).
'new'+'land'='newland'
'found' placed inside 'newland' is 'NEWFOUNDLAND'.
(Other definitions for newfoundland that I've seen before include "Province of Canada" , "Canadian province and island" , "Canadian isle and province" , "Large island part of Canada's most easterly province" , "Canadian province; breed of dog" .)