Overview
Three Rock is the Dublin summit with the mast farm on top, and the view that makes the masts worth ignoring. On a clear evening the whole of Dublin Bay lies below, from Howth Head round to Bray Head, with the Sugar Loaf and the Wicklow ridges rising behind and the three weathered granite tors that name the hill close enough to scramble on. It reaches about 444 m on the southern edge of the city (Irish: Binn Trí Charraig or Sliabh Ruadh), inside the Coillte-run Ticknock Forest, with trails for everyone from buggy-pushers to mountain bikers.
History and heritage
The tors themselves are pure geology, frost-shattered granite rather than anything built. The summit around them is busier with history than it looks. Four bowl-shaped hollows in the rock – bullauns – date from the early Christian period and were used for grinding grain or herbs. Faint ring forts and hill forts mark older settlement, 19th-century quarry pits near Barnacullia show where building stone was cut for the growing city, and a 20th-century army shooting range operated up here until the 1970s. A small holy well, Grumley’s Well, was once visited for cures for sore eyes.
Walking and cycling
Three Rock sits on both the Dublin Mountains Way (Shankill to Tallaght) and the Wicklow Way, so it is as much a waypoint as a destination.
- The Fairy Castle Loop (5.5 km, moderate) is the standard walk: up from the Ticknock car park through the forest, past the Three Rock tors and on to the Fairy Castle cairn on neighbouring Two Rock (536 m), the high point of the ridge. Allow an hour and a half or so.
- For the easy version, the tarmac road runs almost to the summit and is fine for buggies and wheelchairs as far as the mast barrier; the tors are a short step beyond.
- Mountain bikers have the Ticknock trails, roughly 15 km of purpose-built singletrack and forest road waymarked from the car park. Conditions change after storms, so check the Dublin Mountains Partnership before heading out.
Wildlife and seasons
Badgers, foxes and rabbits work the forest edges; great spotted woodpeckers and nuthatches are in the trees, and peregrine falcons hunt around the masts. Spring brings bluebells under the trees, autumn turns the Japanese larch gold, and winter can strip visibility to nothing – the summit is exposed and the weather changes fast at this height.
Practical information
Getting there and parking
The way in is the Ticknock car park off the R113, open 06:00 to 22:00 (the gate locks at ten). Walking in is free; parking may now cost around €2, so bring a coin or check the sign. Reported space counts vary from about 100 to 190, and it fills at weekends, so come early. From the city centre it is roughly 20 minutes by car. By public transport, the 44b runs to Ballinteer but on weekdays only, leaving a walk up; alternatively take the DART to Shankill and walk 15 minutes to the start of the Dublin Mountains Way. Weekend bus options are thin, so a car is the easy choice.
Facilities and safety
There are no toilets or cafés on the mountain itself. The tarmac road is manageable for wheelchairs and buggies to the mast barrier; past that the ground is uneven and climbs. The mast compound is fenced, so stay on the paths and mind the warning signs. Check the mountain forecast before setting out, and in snow or ice expect the car park to close at short notice. For more walking nearby, Carrickgollogan has woodland trails and old mining ruins a short drive away.
Best of all is the last hour of daylight on a clear evening, when the bay lights up and the car park has emptied – just be back down before the gate locks at ten.