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 day Dublin Bay lies below and the view runs south towards Bray Head, with the Wicklow ridges rising behind and the three weathered granite tors that name the hill close by. 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. Walk around the tors for the view, and stay clear of fenced installations.
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 and the Wicklow Way, so it is as much a waypoint as a destination.
- Coillte lists a moderate 5.5 km Fairy Castle Loop from the Ticknock car park. It passes Three Rock and continues to the Fairy Castle cairn on neighbouring Two Rock Mountain (536 m). Allow an hour and a half or so.
- For a shorter outing, use the forest road to the viewing area and retrace your steps. The road climbs, and the ground around the tors is uneven.
- Mountain bikers have separate signed Ticknock trails from the car park. Conditions change after storms, so check their status with the Dublin Mountains Partnership before riding.
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, normally open 06:00 to 22:00. The Dublin Mountains Partnership lists free parking there, with possible short-notice closure in snow or ice. Check current notices, and leave time to return before the gate closes. Walking in is free. From the city centre it is roughly 20 minutes by car. Public transport options are limited, so check current routes before you travel and expect a walk to the start.
Facilities and safety
The mast compound is fenced, so stay on the paths and mind the warning signs. Check the mountain forecast before setting out. 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, but be back down before the car park gate closes.