Get back control across Georgia (6)
I believe the answer is:
regain
'get back' is the definition.
(I've seen this before)
'control across georgia' is the wordplay.
'control' becomes 'rein' (rein is a kind of control).
'across' is an insertion indicator.
'georgia' becomes 'ga'.
'rein' enclosing 'ga' is 'REGAIN'.
(Other definitions for regain that I've seen before include "Get back (previously owned object)" , "Recover, retrieve" , "Win back" , "Recover - in gear (anag)" , "Possess once more for regina" .)