Cumbrian region (4,8)
I believe the answer is:
lake district
'cumbrian region' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for lake district that I've seen before include "holiday location" , "Area of mountains and meres" , "Cumbrian region" , "Cumbria National Park" , "area popular with ramblers" .)