Ipswich's county (7)
I believe the answer is:
suffolk
'ipswich's county' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for suffolk that I've seen before include "Eastern county" , "S.E. county" , "English county" , "Ipswich's county" , "Part of East Anglia" .)