Girl is going around Rhode Island (4)
I believe the answer is:
iris
'girl' is the definition.
'is going around rhode island' is the wordplay.
'going around' indicates putting letters inside.
'rhode island' becomes 'ri' (US postal abbreviation).
'is' placed around 'ri' is 'IRIS'.
(Other definitions for iris that I've seen before include "plant with showy flowers" , "Nice flower or eye part" , "Rainbow-goddess" , "Circular coloured membrane in the eye" , "Flag - part of eye" .)