Superman's county? (4)
I believe the answer is:
kent
I believe this clue is a double definition.
'superman's' is the first definition.
(I've seen this in another clue)
'county?' is the second definition.
(Kent is an example)
(Other definitions for kent that I've seen before include "Canterbury's county" , "known in Scotland" , "Garden of England - Superman's family name" , "Lear's faithful Earl" , "English architect and landscape gardener" .)