Overview
Two Rock Mountain (Irish: Binn Dá Charraig) rises to 536 m (1,759 ft), the highest point in the Dublin Mountains – and, despite that, one of the more forgiving hills to climb, with a tarmac start you can push a buggy up. Its name comes from the two granite tors on the south-eastern slope. From the summit, known as Fairy Castle, the view runs from Tallaght and Howth in the north to Bray Head, Killiney Hill, the Great Sugar Loaf and the Wicklow Mountains in the south. The hill is a working landscape of red-grouse heathland, shallow bog and native woodland, managed by Coillte and the Dublin Mountains Partnership, who are gradually converting the old commercial spruce plantations into native recreational woodland.
History & Ancient Monuments
The summit cairn is a sub-circular mound of granite and quartz blocks, roughly 27 m across and 3 m high. It crowns a Neolithic passage tomb that has never been excavated. Locally called Fairy Castle, it is the easternmost link in a chain of summit tombs stretching across the Dublin and Wicklow ranges. On a clear day you can trace sightlines to the passage tombs on Montpelier Hill, Tallaght Hill, Saggart Hill and Seahan Mountain.
Older maps refer to the hill as Black Mountain, while scholars propose the earlier Irish name Sliab Lecga (“Mountain of the Flagstones”). This name appears in the early-medieval Metrical Dindshenchas and the saga Togail Bruidne Dá Derga, where Mount Lecga serves as a waypoint for raiders.
On the south-eastern slope lies the Ballyedmonduff wedge tomb, often called the “Giant’s Grave”. Dating to the Bronze Age, it features a three-chamber gallery, a horseshoe arrangement of standing stones and a capstone bearing seven cup-marks. First opened in 1832 and re-excavated in 1945, it was reconstructed to its current form. Antiquarian John O’Donovan once called it “the finest pagan grave in any county”. Other lost monuments include the Greyhound’s Bed, a long cairn destroyed in the 19th century, and a triangular standing stone near the summit.
The mountain also played a part in one of the more dramatic episodes of Irish history. In 1591, Red Hugh O’Donnell escaped Dublin Castle and crossed Two Rock on his way to the O’Toole stronghold at Powerscourt. Recaptured, he made a second, successful escape in January 1592, reaching Fiach McHugh O’Byrne in Glenmalure – losing toes to frostbite on the way. That journey through these hills helped forge the alliance that shaped the Nine Years’ War.
Geology & Landscape
The two granite tors that give the mountain its modern name are the best-preserved examples in the Dublin–Wicklow range. They formed through the long weathering of muscovite-microcline porphyritic granite, which fractured along vertical and horizontal joints to leave the outcrops you see today. The summit plateau shifts from wet heath to blanket bog, while the lower slopes carry a patchwork of ferns, gorse and planted Sitka spruce and pine.
Flora, Fauna & Conservation
The open heathland is important habitat for red grouse, a species protected under Irish law. Their breeding season runs from March to May, and walkers are asked to keep to marked paths to avoid disturbing ground nests. Skylarks and meadow pipits are common in summer, while the bogs shelter invertebrates and wildflowers including heather, bilberry and crowberry. Coillte carries out regular heathland management to hold back scrub and keep the slopes open. To connect people with the changing landscape, the Dublin Mountains Partnership hosts community hikes and guided wellness walks (launched with Aware in 2025).
Walking & Trails
Two Rock is reached by several well-marked routes, with the main trailhead at the Ticknock Forest car park. The Fairy Castle Loop is the one to do – long enough to feel like a proper hill walk, short enough for young kids, and buggy-friendly for the first 3 km.
- Fairy Castle Loop – A 5.5 km moderate circuit of roughly 1½ to 2 hours. The first 3 km follows a tarmac road suitable for prams and young walkers, before turning to gravel and boardwalked sections through the heather.
- Two Rock & Three Rock Loop – An 8 km circuit (about 3 hours) linking the summit with neighbouring Three Rock Mountain via the Dublin Mountains Way, adding another 90 m of ascent and ridge-top views.
- Dublin Mountains Way – The national long-distance trail crosses the summit, connecting Tibradden and Piperstown to the west with Rathmichael to the east.
- Wicklow Way – Runs just west of the peak for anyone extending deeper into the Wicklow Mountains.
Mountain biking is popular on the forest trails, though riders should check the Dublin Mountains Partnership website before heading out, as sections are occasionally closed for weather-related repairs.
Cultural & Audio Experiences
The area has been the focus of recent arts commissions under the dlr Arts Nature and Place series. Visitors can download the Ticknock: What’s Going On? podcast by artists Listen and Breathe, which follows the forest’s changing landscape over millennia; the audio is timed to match the walking pace from the car park to Fairy Castle. Méadhbh O’Connor’s Sky Walkers project adds six meditative poems set to ambient soundscapes, made to be heard while resting on the summit or Three Rock.
Practical Information
Getting there – From Dublin city centre, head south via Marlay Park. Follow signs to Ticknock Forest, turn right at Ballinteer St John’s Clubhouse, and continue on the R113 to the Ticknock car park. The most reliable bus is Dublin Bus route 44B to Ticknock/Glencullen (weekdays only); at weekends, routes 44 and 47 stop near the Blue Light pub (stop 3500), leaving a longer walk up. For car-free options, see Hikes Near Dublin Without a Car.
Parking & Access – The dedicated car park holds 145 spaces and opens daily 06:00 to 22:00. Parking is free according to the Dublin Mountains Partnership, though one recent visitor reported a €2 contactless charge – check the signage when you arrive. The car park fills early at weekends; when it’s full, start instead from Kilmashogue Forest car park, a longer route of about 13 km to the summit and back. The summit coordinates are 53.239034, -6.245014.
Amenities – There are no toilets or bins at the recreation site. Follow Leave No Trace: take all litter and dog waste home. The Ticknock entrance has basic wayfinding maps, but no café or indoor facilities.
Accessibility – The trails are not wheelchair-accessible. The initial 3 km of tarmac is buggy-friendly, but the route to the summit involves steep, uneven ground and boardwalks. Sturdy walking shoes are essential.
Dog policy – Dogs are welcome but must be kept on a short lead at all times, due to grazing sheep and ground-nesting birds.
Seasonal notes – The hill is open year-round. Winter brings strong winds on the exposed summit and ice on the tors. Summer offers the most stable footing, while early autumn brings peak heather colour and the end of the red-grouse nesting period.
Nearby Attractions
- Ticknock Forest – A network of managed woodlands with more walking and cycling routes.
- Three Rock Mountain – A neighbouring peak with its own granite tors, communication masts and 360° views, easily linked via the Dublin Mountains Way.
- Kilmashogue – Home to further prehistoric sites, including a wedge tomb and a historic cemetery.
- Powerscourt Estate – On the historic Red Hugh O’Donnell route, with formal gardens, a 121-metre waterfall and woodland walks.
For the best of the view, time your walk for late afternoon and stay for dusk, when the city lights come on across Dublin Bay – just carry a head torch for the walk down, as the boardwalk sections are unlit.