Maumtrasna (Irish: Mám Trasna, ‘the pass across’) is the highest of the Partry Mountains – 682m (2,238ft) of broad, flat, boggy top with several ridges running off it. What catches people out is the summit itself: it’s a large slab on a rocky outcrop about 70m east-south-east of the cairn, and in the cloud that sits on this hill for much of the year the two are easy to confuse. For the tickers, it carries three of the standard classifications – a P600, a Marilyn and a Hewitt – on a prominence of a little over 600m.
From the top the ground falls away to Lough Nafooey, with the spine of the Twelve Bens to the south-west, the Nephin Beg range to the north, and the Atlantic on the horizon when the air is clear. The summit is really one high point on a long plateau: the ridge runs north to Knocklaur (Cnoc Láir, 518m) and on to Devilsmother, so most walkers here are linking summits rather than treating Maumtrasna as a stand-alone climb.
The pass and the murders
The name marks a genuine crossing – the old pass between the Lough Nafooey and Lough Mask basins, walked for generations by drovers and shepherds moving stock over the spine of south Mayo. The townland on the south bank of the Srahnalong River carries a heavier association. In 1882 it gave its name to the Maumtrasna murders, a series of killings during a violent, unsettled period that became one of the most infamous cases of its era and still surfaces in local memory. There’s nothing to see of it on the hill, but it’s why the name is known well beyond Mayo.
The walk
The standard outing is a loop of around 10km with something over 600m of climbing, roughly three hours for a fit walker and longer when the ground is wet, which it usually is. There’s parking at Glencullin Bridge (grid L935 656), but a ‘no parking’ sign appeared there around 2020 – check on arrival, and if it’s still up, use the alternative start on the approach from the Tourmakeady side.
The climbing is steady rather than steep. The plateau is the catch. It’s featureless blanket bog with few reliable landmarks, and in mist it’s one of the easier Irish hills to lose your bearings on completely. Carry the OS Discovery Sheet 38 and a compass and know how to use them, or a loaded GPS track – and don’t stake the day on a phone alone. If you do one thing before the cloud drops, take a bearing off the summit for the way back.
On the hill
Heather and gorse on the lower slopes give way to bog cotton, sphagnum and mountain grasses higher up, with pale quartzite breaking through the peat. Red grouse clatter out of the heather and golden plover work the open tops; peregrine and merlin hunt the slopes, and sheep graze the higher pastures year round. There are no toilets, cafés or shelter anywhere on the mountain or at the trailheads, so carry what you need – Westport, about 45 minutes’ drive, is the nearest town for a proper feed.
Getting there and nearby
The trailheads sit roughly 30km north-west of Westport, reached on minor roads off the R335; public transport is effectively nil, so you’ll be driving. If Maumtrasna is part of a bigger hill day, Ben Gorm and Ben Creggan give steeper, more dramatic climbs nearby, and Ben Bury is the quieter option. Down at valley level, Aasleagh Falls on the Erriff is a five-minute stop worth making after rain, when the river is up.
Access is free and needs no permit, but the weather makes the rules here. Start before midday to stay ahead of the afternoon cloud, and if the top is already in it when you reach the plateau, be honest about your navigation before you commit to crossing it.