Overview
Ireland’s tallest waterfall is here, and in the right wind it runs the wrong way. Sruth in Aghaidh an Aird – ‘the stream against the height’ – drops about 150m off the Dartry plateau above Glencar, but only after heavy rain, and when a strong southerly slams into the cliff it lifts the falling water back over the lip. Locals call it the Devil’s Chimney. That contrariness is the whole range in miniature: a dissected limestone plateau on the Sligo–Leitrim border, cut into cliffs, glacial valleys and flat-topped summits.
Truskmore is the high point at 647m, but it carries a television mast and a service road to the top, so the peaks that draw walkers are Benwiskin (514m) and Tievebaun (611m). If you have one dry day, make it the Gleniff Horseshoe under Benwiskin: the scenery for the effort is the best the Dartry offers, and you can do it on two legs or four wheels.
Benwiskin: the frozen wave
Benwiskin dominates the northern edge of the Gleniff valley, its tilted, wave-shaped crest earning it the nickname the Frozen Wave. The peak sits across the valley from Benbulben, and the pair make one of the most photographed mountain profiles in the north-west. The ridge is heavily peat-covered, giving it a dark, textured look against the pale limestone outcrops lower down.
Most walkers take it in on the Gleniff Horseshoe, a loop of quiet country roads, forest track and open moorland with repeated views out over Donegal Bay and, on a clear day, north to the cliffs of Slieve League. The valley floor still carries the ruins of the Gleniff barytes mine and mill, worked on and off for close to a century, so the walk doubles as a bit of industrial archaeology. Prehistoric tombs – court cairns and dolmens – and old field walls scattered through the area mark how long people have lived off this ground. High in the cliffs of Annacoona sits Diarmuid and Gráinne’s cave, one of the highest caves in Ireland and tied to the legend of the two mythic lovers. It is on private land and the steep, unmarked approach is genuinely dangerous, so admire it from below rather than trying to reach it.
Tievebaun: the white side
Straddling the Sligo–Leitrim border, Tievebaun (Irish Taobh Bán, ‘white side’) takes its name from the bright limestone that dominates its northern face. It is the highest independent summit in Leitrim, and its northern edge throws up the arrow-shaped Eagle’s Rock and the jagged pinnacle known as Hag’s Leap. A low stone wall traces the old county boundary along parts of the ascent.
The usual approach starts near Glencar and climbs through forest onto open bog and ridgeline. Expect steady gradients and long stretches of soft, wet ground; sturdy waterproof boots are not optional. From the summit cairns the view runs from the Sligo coast across the Glenade valley to Benbulben in the west. Somewhere on the Truskmore–Tievebaun tops lies a darker piece of history: on 9 December 1943 a USAAF B-17 Flying Fortress crashed here in poor weather, killing three of the crew, and scattered wreckage remains on the mountain to this day.
Landscape and geology
The Dartry is Carboniferous limestone, dissected into a plateau and then carved by Ice Age glaciers into the deep U-shaped valleys and horseshoes you see today. Thousands of years of weathering and peat growth gave the range its muted greens and browns, broken by the white of exposed rock. The whole area is a Special Area of Conservation and a Special Protection Area, and it holds recognised County Geological Sites at Gleniff Valley and the Glencarbury barite mine.
The limestone soils carry a hardy mix of heath and grassland: wild thyme, bell-heather and cowslips on the lower slopes in early summer, sphagnum moss and bog cotton in the wet hollows. Keep to established tracks on the higher ridges – the blanket bog is fragile and slow to recover once churned up.
Planning your visit
- Access and parking: There is no large dedicated car park for the hills. Informal parking exists around the Gleniff Horseshoe and near Glencar, but spaces are limited; park considerately and never block a farm gate or passing place.
- Getting there: Sligo town, about 20km west, is the natural base. You will want your own transport – public links to the trailheads are sparse, and a car gives you the flexibility the weather demands.
- Walking difficulty: Both peaks are moderate. The Gleniff Horseshoe is a gentle circuit on tracks and lanes; the Tievebaun route is steeper with boggy ground that turns slick in the wet.
- Navigation and safety: Mountain weather turns fast here. Carry waterproofs, a map and compass, and a charged phone. The higher ridges are exposed to wind and rain. Winter is for experienced walkers only.
- What to pack: No facilities on the mountains. Bring water, food, a basic first-aid kit, and a headtorch if you are out early or late in autumn.
Nearby attractions
- Benbulben Forest Walk – a gentle, accessible loop at the foot of Sligo’s most famous mountain, good as a warm-up or a family outing.
- Ballygawley Mountains – a short drive south, with quiet ridge walks and forest trails.
- Carrowmore Megalithic Cemetery – one of Ireland’s largest passage-tomb complexes, older than the pyramids, on the plain below the range.
- Sligo town – the base for beds, pubs and food, with a compact centre and a waterfront walk.
Time a visit for the day after heavy rain if you want the Devil’s Chimney at full roar – most of the year it is a dry cliff, and the wind-blown version only shows up when a big southerly meets a swollen stream.