Overview
Slemish Mountain dominates the flat landscape of the Antrim Coast and Glens, its conical shape rising abruptly from the surrounding farmland. At 437 m (1,434 ft), it is the highest point for miles around and is easily visible from the coastal road and nearby towns. The mountain is most famous for its connection to early Irish history: it is widely believed to be the hill where a teenage Saint Patrick spent six years as a slave-shepherd before escaping to Gaul.
The well-trodden 1.2-mile (≈1.9 km) loop walk starts at the base car park and takes about an hour to reach the summit. Hikers are rewarded with sweeping views of the Antrim countryside, the distant Scottish coast, and, on clear days, the Sperrin Mountains.
Geology: A Volcanic Plug
Slemish is the exposed plug of a basaltic volcano that was active more than 50 million years ago. Over millennia, the softer surrounding rock eroded away, leaving the steep, almost sheer hill that can be seen from up to thirty miles on a clear day. The hard dolerite core gives the summit its rugged character and creates a dramatic visual contrast between the smooth agricultural plains and the rocky upper slopes. This geological resilience is what has preserved Slemish as a prominent landmark long after the rest of the volcanic system disappeared.
History: The Holy Hill of St Patrick
The mountain’s Irish name, Sliabh Mis, means “Mis’s mountain”, a reference that predates the Christian era. According to early Irish tradition, the 16-year-old Patricius was captured by pirate raiders in 406 AD, taken to the north-east of the island, and forced to tend sheep on Slemish for a local chieftain named Milchu (also recorded as Miliucc). Some sources give the slave name Succoth.
During those six solitary years, Patrick turned to constant prayer, a spiritual awakening that later underpinned his missionary work across Ireland. A nearby early-Christian site, Skerry Churchyard, is thought to be one of the first churches he founded after his return. The mountain became known as the “Holy Hill of St Patrick” and remains a pilgrimage destination to this day.
Walking the Loop
The route is often referred to as the Slemish Mountain Loop Walk. While the lower sections follow a grassy track, the upper slopes are rocky and occasionally require light scrambling. There is no formal way-marked trail; walkers choose their own line up the mountain, with the south-western approach favoured for its gentler gradient.
- Navigation – The free ActiveME app provides a GPX/KML file and live map for the 2 km loop. A printed map is also available at the car park.
- Dog-friendly – Dogs are welcome but must be kept on a lead, particularly due to the surrounding farmland and wildlife.
- Facilities – A large free car park, toilets, a picnic area, and interpretation boards are situated at the trailhead.
- Safety – The path can become very slippery in wet weather. Sturdy, grippy walking shoes and waterproofs are essential. The descent can be trickier than the ascent when the ground is wet, so take your time on the way down.
Flora & Fauna
The open heath and grassland support a range of upland birds. Walkers often spot wheatears, meadow pipits, buzzards, and ravens circling the summit. Irish hares are a regular sight in the surrounding plains. The sparse vegetation and exposed rock also provide a good opportunity for wild-flower spotting in late spring, when the hardy flora begins to bloom.
St Patrick’s Day Pilgrimage
The annual pilgrimage on 17 March draws over a thousand participants. Since 2025, the event has operated a Park & Ride service from the Silverwood/Michelin site on Raceview Road, Broughshane (off the M2). Buses run from 9 am until the last departure at 3.30 pm.
On-site parking at the summit is closed for the day; only blue-badge holders and service/assistance dogs may use the designated area. The event includes a petting farm, face-painting, traditional Irish music, and a marquee for dancing. Climbers who reach the top receive a St Patrick’s Day certificate (subject to availability). Throughout the rest of the year, smaller groups and guided walks are organised by local heritage groups, offering a quieter way to explore the slopes.
Practical Information
| Item | Details |
|---|---|
| Length | 1.2 mi (≈1.9 km) round-trip |
| Estimated time | 1 – 1.5 hours |
| Elevation gain | 166 m |
| Difficulty | Moderate – steep and rocky |
| Parking | Free car park with toilets and picnic area (restricted on 17 March – use park-and-ride) |
| Admission | Free |
| Dog policy | Dogs allowed on lead |
| Best season | Late spring to early autumn; 17 March for pilgrimage |
| Navigation | Trail is unmarked; use ActiveME app or printed map |
| Facilities | Toilets, picnic tables, interpretation boards |
Getting There
From Ballymena, follow the A42 eastwards for about 8 km, then turn onto the B94 towards Broughshane. Signage for Slemish Mountain appears shortly after the turn. The car park is clearly signposted and located at the base of the southern slopes.
Nearby Attractions
After the climb, the region offers a wealth of sights within a short drive. The town of Ballymena provides excellent dining and shopping options, while Ballymena Castle offers a glimpse into the area’s architectural history. For coastal scenery, head north to Antrim Castle or explore the heritage trails in Armoy. The wider Antrim Coast and Glens area is home to world-famous landmarks like the Giant’s Causeway and Dunluce Castle.
Safety Notes
The path is not wheelchair-accessible and can be hazardous when wet. Walkers should stay on the established route, watch for loose stones, and be prepared to turn back if weather deteriorates. Mobile phone signal can be intermittent on the summit, so it is wise to download offline maps before starting the ascent.