Overview
The Glen of the Downs is that rare thing: a woodland walk beside the N11. Within a few minutes of leaving the road the traffic noise gives way to the murmur of the Three Trouts River. The glen (Irish: Gleann dá Ghrua, ‘valley of the two brows’, for its two steep facing slopes) is a glacial valley in County Wicklow whose slopes hold oak woodland protected within the Glen of the Downs Special Area of Conservation.
The woodland is dominated by sessile oak on acid soils, with an understorey of holly, bilberry and heather. It is one of the few places within reach of the city where you can walk a mature broadleaf forest of oak, ash, cherry and rowan and stand a fair chance of a red squirrel. If you have an hour, this is the one thing to do: the woodland is the whole point, and the climb pays off with views over the Wicklow landscape.
The Walk & Trail
Use Wicklow’s visitor guidance and the signed entrances to plan a route. Check current works and parking before setting out, keep to established tracks and leave the road clear. Most visitors take about an hour for a woodland circuit, though the path invites lingering at several lookout points.
The early section of the walk runs close to the N11, but the dense tree cover soon dampens the sound. As you climb, the path winds through a carpet of bilberry, wild garlic and woodrush. The upper reaches of the trail open up to wider vistas, and on a clear day the Great Sugarloaf dominates the view.
Paths can be steep, wet and uneven. The ground can be soft and muddy after rain, so sturdy, waterproof footwear is essential. The trail involves inclines and uneven terrain that make it unsuitable for wheelchairs or pushchairs. Keep back from the steeper edges around the high ground.
History & The Octagon
The glen sits between two Bronze-Age hillforts, Coolagad and Downshill. Local tradition puts the Battle of Delgany (1022) here, where Sitric Silkenbeard, King of Dublin, clashed with Uagaire, King of Leinster.
Centuries later, in the mid-18th century, the land became part of the Bellevue Estate. Dublin banker David La Touche purchased the 300-acre property in 1753 and built Bellevue House the following year. The estate’s most enduring feature is the stone Octagon, built by the La Touche family in 1766. Also known as Hangman’s Rock, the eight-sided viewpoint stands above the glen, and local tradition holds that highwaymen were hanged there, a sombre note in an otherwise gentle setting.
Bellevue House fell into ruin by the 1950s, and the Irish state eventually acquired the core of the estate. The Glen of the Downs was formally designated as a Nature Reserve in 1980, protecting the woodland for future generations.
Nature & Conservation
The Glen of the Downs is a stronghold for native wildlife. The mature oak canopy supports an understorey of holly, honeysuckle, ivy and wood sage. Botanists visit to spot rarer species such as Turner’s Threadwort (Trichocolea tomentella), a liverwort that is scarce nationwide.
Animal sightings are possible for those who walk quietly. Red squirrels are often spotted in the branches. Sika deer, foxes, badgers and otters also inhabit the area, while the elusive pine marten may be seen near the river. Birdwatchers can expect to hear blackbirds, chaffinches, jays, treecreepers and wood warblers, with occasional sightings of red kites circling above.
Recent Expansion
In December 2025 the National Parks and Wildlife Service announced that it had acquired 40 hectares adjoining the reserve. The land is former commercial conifer forestry. The purchase does not itself establish access to new trails, so follow the current route signs and land notices rather than exploring the new ground.
Practical Information
- Getting there: The glen is beside the N11 in north County Wicklow. Use the signed nature reserve access, keep the N11 clear and check current works and parking before you set out.
- Public transport: Greystones is the nearest DART station; check current bus links and timetables before you travel.
- Facilities: Check the Visit Wicklow listing for current facilities and notices.
- Admission: Free entry to the reserve.
- Duration: Allow 60–90 minutes, depending on your pace and photo stops.
Nearby Attractions
Greystones is ten minutes south, with a harbour, beach and plenty of places to eat once you’re back from the woods. For more high ground, the Great Sugarloaf rises just west of the glen and is climbed from Kilmacanogue, a short, steep climb to a proper summit view. Further inland, Glendalough and its monastic ruins make an easy half-day extension.
Bring a waterproof jacket whatever the forecast, as the valley floor stays damp beneath the oak canopy even on dry days.