Dún Laoghaire's land (4)
I believe the answer is:
eire
'dun laoghaire's land' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for eire that I've seen before include "Southern Ireland" , "Former name of the Irish Republic" , "Republic across the water" , "Irish name for Ireland" , "Land" .)