Overview
The point where three counties meet on Sliabh Beagh has a name: the Three County Hollow, a flat, windswept depression where Monaghan, Fermanagh and Tyrone all touch. It sums up the place – low, boggy, exposed, and far more remote-feeling than its closeness to main roads suggests. Sliabh Beagh (Irish: Sliabh Beatha) is a plateau of blanket bog, peat-clad hills and shallow upland loughs, topping out at 380m (1,250ft). The true summit sits on the Fermanagh–Tyrone border; the highest ground in County Monaghan is a point just east of it.
The land is protected as both a Special Area of Conservation and a Ramsar wetland of international importance – a mosaic of sphagnum moss, dwarf heath and shallow streams that feeds the Finn River and shelters some of Ireland’s more elusive upland birds. If you only have a couple of hours, walk the short forest loop at St Patrick’s Chair and Well above Altadaven Wood; it packs the best of the human history into an easy circuit.
History and mythology
The name Sliabh Beatha is usually read as ‘mountain of birch’, but folklore gives it another root: Bith, a mythic figure said to be a son of Noah, reputedly buried in a summit cairn known as the Cairn of Doocarn.
The plateau carries the weight of the penal era too. Leacht a’tSagairt (the Priest’s Stone) is a Mass rock topped by a large Celtic cross. Tradition holds that a priest-hunter shot the priest – named as Fr McKenna – while he was saying Mass here on Christmas Day around 1754. The nearby Bragan Penal Cross marks the same killing. The priest-hunter was later run down and killed near Emyvale by the rapparee leader Shane Bernagh (also recorded as Shane Barnagh), who used this rough country to stay ahead of the law.
Further along the ridges, St Patrick’s Chair and Well sits above Altadaven Wood – a boulder-hewn seat and holy well thought to predate Christianity and later folded into Patrician tradition. In 2000 the People’s Millennium Forests scheme planted native saplings in the Favour Royal Forest, one tree for every household in the country, restoring a fragment of the woodland that once covered these slopes.
Walking the trails
Routes here run from gentle family strolls to a serious multi-day trek. The long one is the Sliabh Beagh Way, which Discover Northern Ireland puts at about 40 miles (64km) – a two-day walking route over country lanes, forest tracks and a remote path across the open moor. It begins in Aughnacloy, County Tyrone, reaching St Patrick’s Chair and Well on the first section, then works south-west through the drumlins of Monaghan and the lakeland of County Fermanagh to finish near Donagh. Sustained ascents, exposed peat and uneven forest tracks make it a real undertaking; most walkers spread it over two or three days, or use the waymarked loops as shorter alternatives.
For single-day outings, the wider region has some 36 waymarked loops, ranging from 4km to 15km and colour-coded by difficulty:
- 4km easy – A gentle forest circuit around St Patrick’s Well, good for families and dogs.
- 6.5km – Winds past small cairns with ridge views over the border counties.
- 10km – A mixed route through forest and open bog with frequent lake views.
- 15km hard – An extended ridge walk through Mullaghfad Forest and past several upland loughs, best kept for dry conditions.
Trails are marked with the orange-and-green Sliabh Beagh logo. Waymarking is clear, but carry an OS map (Series 44) or a downloaded GPS track – the terrain turns disorienting in mist.
Key sites and landmarks
- St Patrick’s Chair and Well – At the southern end of Altadaven Wood, reached by a short marked path from the car park. The ancient seat is still a spot for quiet reflection.
- Bragan Penal Cross – Signposted from the R186, standing in a remote, atmospheric setting. A short detour from the main trail makes it a rewarding stop.
- Muckle Rocks and Shane Barnagh’s Lough – An outcrop tied to the outlaw legends, reached by a moorland track past Bragan. A footbridge crosses the Coolbrooke River nearby.
- Mullaghfad Forest and lakes – Lough Cushkeery and Jenkin Lough draw birdwatchers and red-squirrel spotters; the forest car park is a handy trailhead for the longer loops.
- Tully Forest – Near the midpoint of the long-distance way, a known stronghold for native red squirrels; early morning gives the best chance of seeing them.
- Mullaghfad Church – A remote 19th-century stone church ringed by old yews, with a small parking area off the route.
Wildlife and nature
The bog and lake system supports more life than the bare moor suggests. Hen harriers quarter the heath, and golden plover and red grouse nest on the open ground. The replanted native woodlands have drawn back red squirrels, occasionally seen along the forest tracks. Nesting activity peaks from late spring to early autumn, when the heather also comes into bloom. Early-morning mist over the loughs makes for good photography without any special kit.
Practical information
- Getting there – The R186 from Monaghan and the A34 from Northern Ireland are the main road access. Designated car parks are at Altadaven Wood (southern entrance), Mullaghfad Forest and near the Bragan Penal Cross.
- Navigation – All routes are waymarked. Carry a physical map or offline GPS; mobile coverage is patchy across the moor.
- Facilities – Picnic tables and basic toilets at Altadaven Wood and Mullaghfad Forest. There are no cafés on the trail, so bring water and food.
- Seasonality – The bog becomes waterlogged and treacherous in winter. Late spring to early autumn gives the firmest ground and longest daylight. Guided walks run during events such as the Sliabh Beagh Walking Festival in April.
- Safety and conservation – Weather changes fast up here. Waterproof boots, layers and a compass are essential. As a protected SAC and Ramsar site, stay on marked paths, keep off the sphagnum and take all litter home.
If you are short on time, stick to the waymarked loops; allow at least two days for the full Sliabh Beagh Way. Check both the Met Éireann and Met Office forecasts before you set out – visibility can drop to near zero in the hollows.