Mythical hunter from America, in American capital (8)
I believe the answer is:
atalanta
'mythical hunter' is the definition.
(I've seen this in another clue)
'america in american capital' is the wordplay.
'america' becomes 'a' (common abbreviation eg in USA).
'in' indicates putting letters inside.
'american capital' becomes 'Atlanta' (state capital of Georgia).
'a' inserted within 'atlanta' is 'ATALANTA'.
'from' acts as a link.
(Other definitions for atalanta that I've seen before include "Legendary runner outwitted" , "Greek runner" , "Greek huntress defeated in a running race" , "fast woman" , "Mythological fast-running girl" .)