The Poisoned Glen is one of Donegal's oldest established climbing venues and provides huge alpine length routes in a superb mountain setting. The routes are long with excellent quality rock and at times, complex route finding. The main face faces north and receives very little direct sunlight and as such near-drought like conditions are required to find the rock dry enough to climb.
The Poisoned Glen is one of Ireland's original climbing venues with routes dating back to the 1950s and 1960s. The glen also plays host to Ireland largest continual rock face (The Bearnas Buttress) and Ireland longest Ice climb. (Donegal Winter climbs guidebook)
The best approach into the Poison Glen on your first visit is from the Dunlewey side, from the R251 at the base of the south face of Errigal follow the wee side road down to the ruined roofless church. From here follow the road and path into the glen. This allows a first-time visitor a very good look at all the crags from their bases on the approach. The crags are generally easier to approach from the Bingorms side and access details are in each crag section.
The highest crag is also the fastest drying, Ballaghageeha Buttress sits at an altitude of 400m and provides excellent single and multi-pitch climbing. It has in recent years seen a lot of attention from local climbers and as such most of the routes are freshly cleaned.
The Poison Glen catches all the moisture brought into Donegal by the North Atlantic Drift and it can be a very wet place indeed. If the glen is wet a few alternative places to climb are Bingorms, Glenveagh or
Muckish Mountain BUT these locations are prone to the same climatic downpours as the Poison Glen.