Overview
Mullacor is not a mountain most people climb for its own sake. It is a high point of the broad horseshoe of ridges around the Upper Lake of Glendalough, and it tends to get bagged in passing, on a long circuit from Glendalough, on loops out of Glenmalure, or on the Wicklow Way, which crosses its saddle. The name is Mullaigh Mhór, ‘big hilltop’, which about covers it. There is a summit cairn, a boggy plateau, and a view down into Glenmalure and across to Turlough Hill and Lugduff. The photograph above looks from Mullacor towards Barravore Ridge and Fraughan Rock Glen. It shares the horseshoe with Lugduff, Conavalla, Turlough Hill and Camaderry.
Landscape and geology
The rock underfoot is dark blue-grey slate, phyllite and schist, not the quartzite of some Wicklow tops, and the last Ice Age did the shaping, grinding out the ridges and scattering the erratics that still litter the slopes. This is open, exposed ground once you leave the forestry: heath and rough grass up to a summit that holds water. Red deer range the area, and local lore keeps a white deer among them. The Derrybawn woodland trail is one way up through the trees before the ridge opens out.
Choose a marked walk
Mullacor lies inside the Wicklow Mountains National Park. Use the national park’s marked trails at Glendalough and check the route grade before starting. The terrain shifts fast from forest track to windswept heath, so conditions change with the season and the weather.
The NPWS closure notice lists closures of the white, blue and red Spinc routes for helicopter operations, including a morning closure on 6 November 2026. Check it for any further dates. Check the separate White Trail works notice for longer-running disruption. Follow the current notices, keep dogs on a lead throughout the park and stay on marked paths.
Whichever route you take, the last pull to the cairn crosses a wet, mossy plateau that turns to bog after rain, so boots with real grip earn their keep. Cloud drops quickly here in summer and ice lingers in winter, so carry a map and compass or GPS and know how to use them. This is not ground for wheelchairs or buggies.
Practical information
Getting there and parking – check the national park website for current parking arrangements at Glendalough. Car parks fill early on fine weekends, so arrive early in summer.
Public transport – check current timetables before you plan a day around buses to Glendalough, as services change.
When to go – summer gives the longest daylight and the driest ground; winter demands full mountain kit and the experience to use it in snow or ice.
Nearby
If the legs have anything left, the Upper Lake of Glendalough sits below the trailheads and mirrors the peaks on a still morning; the monastic city beside it keeps its round tower and early medieval ruins. For a softer afternoon, Avondale Forest Park has easy woodland trails and Avondale House, birthplace of Charles Stewart Parnell, a short drive off.
Start early, and treat Mullacor as one top on a bigger round rather than a destination in itself. Check the Met Éireann forecast first: Wicklow weather turns regardless of the season.