Overview
The Glen of the Downs is that rare thing: a proper woodland walk you can reach without leaving the N11. Turn off at Exit 9 and within a few minutes 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 sides rise almost 250 metres, sheltering one of the finest sessile-oak woods near Dublin.
This is a Special Area of Conservation dominated by sessile oak on acid soils, with an understorey of holly, bilberry and heather. It’s 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. A December 2025 land purchase grew the reserve by 40 hectares to around 100 hectares in total; the older heart of the reserve is 59 hectares of native woodland. The walk itself is the 3.6km loop that climbs from the valley floor to views over the Great Sugarloaf. If you have an hour, this is the one thing to do — the woodland is the whole point, and the climb pays off at the top.
The Walk & Trail
The reserve is best explored via the main circuit walk, which starts from the car park on the eastern side of the valley. The trail is clearly signposted and offers a moderate challenge with about 110 metres of ascent over the 3.6km route. Most visitors complete the loop in about an hour, 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 panoramic vistas across the Wicklow landscape. On a clear day, the Great Sugarloaf dominates the view, a fitting reward for the climb.
The ground can be soft and muddy after rain, so sturdy, waterproof footwear is essential. While the car park area is flat and accessible, the main trail involves inclines and uneven terrain that make it unsuitable for wheelchairs or pushchairs.
History & The Octagon
The glen sits between two Bronze-Age hillforts, Coolagad and Downshill, dating to around 3,000 BC. 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 trail, 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 a rich understory of holly, honeysuckle, ivy, and wood sage. Botanists visit to spot rarer species such as Turner’s Threadwort (Trichocolea tomentella), a liverwort found at only five sites nationwide.
Animal sightings are common for those who walk quietly. Red squirrels are frequent visitors, often spotted darting through the upper branches. Sika deer, foxes, badgers, and otters also inhabit the reserve, 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
The reserve continues to grow. In December 2025, the National Parks and Wildlife Service acquired an additional 40 hectares of adjoining land, increasing the reserve’s size by 68%. This new area, previously used for commercial conifer forestry, is being gradually converted back to native sessile-oak woodland. The expansion also allows for the removal of invasive species like cherry laurel and the conservation treatment of the historic Octagon, which is listed as a protected structure in the Wicklow County Development Plan.
Practical Information
- Getting There: The main car park is on the eastern side of the valley, directly off the N11 at Exit 9 (Glenview). It holds roughly 30 vehicles, so arrive early on weekends.
- Parking: The official site lists entry as free, but some recent visitors report a small parking charge — carry a few coins or a card just in case.
- Public Transport: The nearest DART station is Greystones. From there, Bus Éireann route 84 runs to the reserve’s car park in about 10 minutes, and taxis are available from the station.
- Facilities: There is an information board at the car park with the trail and local history. There are no café or toilet facilities on-site, so plan accordingly.
- Admission: Free entry to the reserve.
- Duration: Allow 60–90 minutes for the full loop, 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 scramble 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 — the valley floor stays damp beneath the oak canopy even on dry days — and go early on busy weekends to be sure of a parking spot.