Island north of Montecristo (4)
I believe the answer is:
elba
'island north of montecristo' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for elba that I've seen before include "Island in the Med" , "place for Napoleon" , "Italian isle" , "Napoleonic island" , "part of Tuscany?" .)