Prospect first seen in Virginia (5)
I believe the answer is:
vista
'prospect' is the definition.
(synonyms)
'first seen in virginia' is the wordplay.
'first' becomes 'ist' (ist resembles 1st).
'seen in' indicates putting letters inside.
'virginia' becomes 'va' (US state abbreviation).
'ist' going within 'va' is 'VISTA'.
(Other definitions for vista that I've seen before include "A view as seen through a long narrow opening" , "Distant view" , "Pleasant view" , "View (with avenue)" , "Panorama" .)