Loch Coulin is in small irregular shaped loch that opens to north-east facing channel that is some 200 metres wide, that progressively reduces in width, before finally becoming a small river before it meets
Loch Clair. The River Coulin is the primary inflow to the loch at the south-east end of the loch along with Allt na Fèithe Buildhe. To the north-east is bounded to the north by a mountain massif in the
Torridon area that contains the highest peak of
Beinn Eighe, that is within
Beinn Eighe National Nature Reserve. To the west of the loch is Sugrr Dubh at 782 metres. To the south is a continuation of the mountainous Coulin Forest, with Meall an Leathaid Mhòir at an altitude of 512 metres. To the south is a continuation of the mountainous Coulin Forest, with Meall an Leathaid Mhòir at altitude 512 metres and a series of small hills forming a ridge in an east to west direction. To the east is a boggy flat plain. ==Walking==