Overview
The Horses’ Glen, known in Irish as Gleann na gCappel (the Glen of the Horses), is a dramatic, dog-legged glacial valley carved deep into the western shoulder of the Mangerton massif. Located just a short drive from Killarney, this rugged trough offers a stark, wild contrast to the gentler, wooded lakeside paths of the nearby national park.
While most visitors to Mangerton stick to the popular summit track, those who venture into or around the rim of the Horses’ Glen find a starkly beautiful landscape of towering red sandstone cliffs, bright veins of volcanic rock, and three dark, cold mountain tarns resting at different elevations on the valley floor.
Mythology of the Massif
The dramatic topography of the Mangerton massif has long inspired local folklore. According to Irish mythology, the deep, circular corrie lake known as the Devil’s Punchbowl – which sits just west of the glen – was formed during a dispute between a local chieftain, O’Donoghue Ross, and the Devil.
The story goes that after dining together one evening, the chieftain punched the Devil in the face. Enraged as O’Donoghue Ross made his escape, the Devil bit off the very top of Mangerton Mountain and hurled it at the fleeing chieftain. His aim was off; the massive chunk of rock missed O’Donoghue Ross entirely and landed far to the east in County Tipperary, where it became the famous Rock of Cashel, leaving behind the deep, water-filled hollow of the Punchbowl.
A 400-Million-Year Geological Story
The physical reality of the glen is no less extraordinary than the myths. The rocks here tell a story of continental drift, volcanic eruptions, and ice.
During the Devonian period, some 400 million years ago, this portion of Ireland lay at the centre of the super-continent Pangea. A hot, arid desert climate prevailed, depositing vast quantities of sand that eventually compacted into the Old Red Sandstone that dominates the Munster landscape. Tectonic plate collisions later crumpled these horizontal layers into the massive ridges of the Armorican Fold Mountains.
This tectonic activity was accompanied by violent volcanic eruptions. Much of the rock between Mangerton and Beenaunmore to the east is rhyolite, a light-coloured, silica-rich volcanic rock. Where glacial scouring has stripped away the topsoil, these bright igneous veins contrast sharply with the dark red sandstone, giving the cliffs of the Horses’ Glen a distinctive, luminous quality.
The final shaping of the glen occurred during the last Ice Age. Glaciers scoured out deep rock basins, creating the hollows that now hold Lough Erhogh and Lough Managh. As the ice melted, torrential meltwaters ripped through the valley, carving a tight, V-shaped exit gorge. Meanwhile, a terminal moraine – a massive wall of glacial debris – blocked the mouth of the valley, trapping water to form the lowest of the three lakes, Lough Garragarry.
Choosing Your Hiking Route
Walks in the Horses’ Glen start and finish at the concrete bridge over the Finnoulagh River (grid reference 984 847). Because navigation can be exceptionally difficult in mist or low cloud, hikers should always carry Ordnance Survey Discovery Series maps (Sheets 78 and 79) and a reliable compass.
The Glen Floor Walk (Fisherman’s Path)
- Distance: 8 km
- Time: 4–5 hours
- Ascent: 700 m
- Difficulty: Hard (sturdy boots and full wet-weather gear are essential)
This route takes you directly into the heart of the valley. From the concrete bridge, follow the main Mangerton track for roughly one kilometre up to the 350-metre contour line. From here, strike out east across the open hillside toward Lough Garragarry.
Near the lake shore, you will pick up an old fisherman’s path. This faint track guides you along the base of the towering cliffs, squeezing through the narrow, V-shaped gap where the valley closes in, before opening up again at Lough Managh. Continue contouring above the water to reach the upper glen and the high mountain tarn of Lough Erhogh. The high ground between these two upper lakes is the perfect spot to pause and appreciate the sheer scale of the surrounding rock walls.
To return, you can climb the steep, pathless slope directly behind Lough Erhogh, or follow a narrow sheep track that contours around the valley wall onto the arête separating the glen from the Devil’s Punchbowl. From there, turn right toward Mangerton North Peak and descend the heathery slopes to rejoin the main track.
The Rim and Ridge Circuit (Stoompa & Mangerton Loop)
- Distance: 14 km
- Time: 5–6 hours
- Ascent: 850 m
- Difficulty: Strenuous
For those who prefer ridge walking and high-altitude views, the full circuit around the rim of the glen is one of the finest hill walks in Kerry.
Follow the main Mangerton path until you reach a large boulder with a metal stake embedded in it. Veer left here, crossing the boggy ground along the 270-metre contour toward the outlet of Lough Garragarry. Crossing the lake’s outflow can be tricky; the stepping stones are small and can be submerged after heavy rain. If the water is too deep, walk south along the western shore, cross where the stream is narrower, and walk back along the eastern shore before beginning your climb.
From the lake, ascend the long, grassy spur to the summit plateau of Stoompa (705 m). The views from this ridge are spectacular, looking directly down into the vertical cliffs of the upper coom and west across Lough Garragarry toward Lough Leane and the MacGillycuddy’s Reeks.
From Stoompa, follow the cliff-edge path southwards to the col. This col offers the single best vantage point in the area, as it is the only spot from which all three lakes – Garragarry, Managh, and Erhogh – are visible at once. Continue up the steep slope toward the Mangerton Plateau, visit the cairn at the Devil’s Punchbowl, and descend via the steep rock steps to the arête. Climb over Mangerton North Peak (782 m) before descending the long, heathery northern spur back to your starting point.
Practical Information
- Getting There: From Killarney, take the N71 Muckross Road south. Turn left at Molly Darcey’s Pub (near the Muckross Park Hotel), then take the immediate first right. Follow this narrow road to the concrete bridge over the Finnoulagh River.
- Parking: There is a tiny parking area immediately beside the bridge, but it fills up very early. Otherwise, parking is limited to narrow roadside lay-bys. Ensure your vehicle does not block farm gates or local traffic.
- Facilities: This is a wild mountain environment. There are no toilets, shops, shelters, or rubbish bins anywhere along the route. Killarney is the nearest option for stocking up on food, water, and supplies.
- Safety: The weather in the Mangerton massif can change rapidly. Sudden gales often whip through the narrow V-shaped gorge of the glen, and the high ridges are completely exposed. Keep well back from the cliff edges, especially in windy conditions.
- Dogs: Dogs are permitted but must be kept under strict control. The terrain features steep drop-offs, deep water, and free-roaming mountain sheep.
Before setting foot on the trail, always check the local weather forecast and assess the water level at the Finnoulagh River bridge; if the river is running high, the lake crossings further up the glen will likely be impassable.