In one area old country has abandoned pit (5)
I believe the answer is:
abyss
'pit' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
(Other definitions for abyss that I've seen before include "Very deep gorge" , "something rather deep" , "Seemingly bottomless chasm" , "Very large and deep chasm" , "Hell; hole" .)