Overview
The Glen of the Downs (Irish: Gleann na nDún) is a striking 2 km long glacial valley on the east coast of County Wicklow. Its steep sides rise to almost 250 m, framing a narrow floor that the N11 dual carriageway cuts between junctions 9 and 10. Designated a Nature Reserve covering 59 ha and a Special Area of Conservation, it protects a rare, drier type of sessile‑oak woodland on acid soils. Broad‑leaf giants – oak, ash, cherry and rowan – dominate the canopy, while a carpet of bilberry, wild garlic and woodrush thrives beneath.
History / Background
The valley sits between two Bronze‑Age hill‑forts, Coolagad and Downshill, each dating to around 3 000 BC. Local legend links these forts to the 11th‑century clash between Sitric Silkenbeard, King of Dublin, and Uagaire, King of Leinster, at the Battle of Delgany (1022). In the mid‑18th century the land became part of the 300‑acre Bellevue Estate, bought by Dublin banker David La Touche in 1753. He built Bellevue House in 1754 and added the distinctive stone Octagon in 1766 – an eight‑sided monument reputedly used for public executions. After the house fell into ruin in the 1950s, the Irish state acquired the core of the estate and opened the valley to the public as a nature reserve.
The Glen of the Downs was formally established as a Nature Reserve by S.I. No. 178/1980. It was one of the first reserves created under the Wildlife Act, recognising the high conservation value of its ancient oak woodland.
Recent Conservation Expansion
In December 2025 the National Parks and Wildlife Service (NPWS) acquired an additional 40 ha of land adjoining the reserve, increasing its size by roughly 68 % to a total of 100 ha. The new area, previously commercial conifer forestry, will be gradually converted to native sessile‑oak woodland using continuous‑cover forestry techniques. This expansion supports Ireland’s Nature Restoration Plan and will protect rare habitats such as the liverwort Trichocolea tomentella (Turner’s Threadwort), recorded at only five sites nationwide. Ongoing works include the removal of invasive cherry laurel and conservation treatment of the Octagon, which is a protected structure in the Wicklow County Development Plan.
What to See & Do
The 3.6 km Loop Walk
A well‑signposted 3.6 km circuit starts from the car park on the eastern side of the valley. The trail weaves through ancient oak groves, climbs gently (≈200 m gain), and passes several lookout points offering panoramic vistas of the Great and Little Sugarloaf hills and the surrounding Wicklow landscape. The early metres are audible from the N11, but the sound quickly gives way to the babble of the Three Trouts River and the chorus of resident birds.
Wildlife Watching
The reserve is a haven for birdwatchers: blackbirds, chaffinches, jays, treecreepers, wood warblers, wrens and occasional kites are common, and the rare wood warbler visits in some years. Mammals include red squirrels, sika deer, otters, foxes, badgers and the elusive pine marten. Botanists will appreciate the diverse understory of bilberry, bramble, wild garlic, holly, honeysuckle, ivy, woodrush and wood sage, as well as rarer fungi and bryophytes such as Turner’s Threadwort.
The Octagon and Historical Markers
A short detour leads to the stone Octagon, an eight‑sided structure built in 1766. Information boards near the car park explain the Bronze‑Age forts, the La Touche family, and the 19th‑century protests that delayed the N11 upgrade. From the Octagon you can glimpse the Great Sugarloaf, a reminder of the French‑derived name “Bellevue” – “beautiful view”.
Getting There
The reserve is accessed via the N11 dual carriageway; the main car park lies on the eastern side, just off Exit 9 (Glenview). For those using public transport, the nearest DART station is Greystones. From Greystones, Bus Éireann route 84 (or local services) runs to the reserve’s car park, a journey of about 10 minutes. Taxis are also readily available from the station.
Practical Information
- Website: Visit Wicklow – Glen of the Downs Nature Reserve (confirmed active)
- Car park: Eastern side of the valley, directly off the N11 (Exit 9 – Glenview). Free parking for roughly 30 vehicles.
- Access: Open year‑round; no formal opening hours.
- Facilities: Information board at the car park; no café or toilet facilities on‑site.
- Footwear: After heavy rain the ground can become muddy; sturdy, waterproof shoes are advisable.
- Accessibility: The flat car‑park area is wheelchair‑accessible, but the ascent to the main trail is not suitable for wheelchairs.
- Duration: The loop can be completed in about an hour at a moderate pace.
- Fees: No admission charge.
Nearby Attractions
A short drive north brings you to the charming village of Avoca Valley, where you can explore the historic Avoca Handweaving Mill and enjoy a riverside walk along the Avonmore.
Enjoy a walk through one of Ireland’s most picturesque oak valleys, where natural beauty and layered history intertwine.