Popular girl in a state (7)
I believe the answer is:
indiana
'a state' is the definition.
(Indiana is an example)
'popular girl' is the wordplay.
'popular' becomes 'in'.
'girl' becomes 'diana' (**).
'in'+'diana'='INDIANA'
'in' acts as a link.
(Other definitions for indiana that I've seen before include "--- Jones, Harrison Ford film character" , "US Midwest state" , "___ Jones, Harrison Ford hero - US state" , "-- Jones, Harrison Ford role" , "State of central US" .)