Overview
The Gleniff Horseshoe is a compact yet spectacular 10 km (about 8.5 km of road) single‑lane loop that winds through a glacially‑carved valley on the northern side of the Dartry Mountains in County Sligo. The journey begins at the Gleniff Barytes Mill Site, where ample free parking and the weather‑worn remains of a 19th‑century barytes mill welcome visitors. From the car‑park the valley opens up to soaring peaks – Benbulben, Truskmore, Tievebaun and the Kings Mountain plateau – with Donegal Bay sparkling on the horizon. Whether you have a half‑hour for a scenic drive or a few hours for a moderate walk, the Horseshoe delivers a vivid slice of Sligo’s rugged beauty.
History / Background
During the last Ice Age, glaciers up to a kilometre thick scoured the Dartry range. Around 10 000 BCE the ice retreated northward, carving the deep U‑shaped Gleniff valley that we see today. In the late 1800s the valley became a centre for barytes (barite) extraction; the heavy mineral was mined from the surrounding hills and processed at the mill that once stood where the car‑park now lies. The mill fell into disuse in the early 20th century, leaving stone foundations and rusted machinery as a tangible reminder of the industrial past.
What to See & Do
| Feature | Details | Why it matters |
|---|---|---|
| Scenic Drive | 30‑minute clockwise loop, ~8.5 km of narrow, well‑maintained road. | Drives towards the centre of the horseshoe give panoramic views of the Dartry peaks, the glen floor and, on clear days, the Atlantic horizon. |
| Benwiskin Trail (9.1 km walk) | Starts at the Barytes Mill car‑park, follows quiet country roads and low‑level forest paths, ~3 hours, moderate. | Provides close‑up vistas of the valley, the dramatic cliffs of Annacoona, small waterfalls, and the iconic Magic Hill illusion. |
| Longer Benwisken Trail (13.6 km walk) | Begins at St Brigid’s Church (Benwisken Centre), adds a stretch of quiet road before joining the main loop, ~4 hours. | Ideal for walkers seeking extra mileage and a quieter start. |
| Magic Hill (Gravity Hill) | Small rise about halfway around the loop, under Tievebaun. | Releasing the hand‑brake on neutral makes the car appear to roll uphill – a quirky optical illusion loved by families and photographers. |
| Diarmuid & Gráinne’s Cave | Natural arch perched ~400 m up the southern slope, visible from the trail. | Legendary hide‑out of the mythic lovers; the climb is steep and on private land, so admire from a safe distance. |
| Historic Mill Remains | Stone foundations and rusted equipment at the car‑park. | Offers a tangible link to the valley’s barytes‑mining heritage. |
| Nearby Attractions | Benbulben Forest Walk, Glencar Waterfall, Devil’s Chimney, Mullaghmore Beach, Classiebawn Castle, and the Carrowkeel Megalithic Complex (all 15‑30 min drive). | Extends the day with coastal walks, historic sites and seaside towns. |
Highlights in Detail
- Diarmuid & Gráinne’s Cave – Local folklore tells that the lovers fled Fionn mac Cumhaill and sought refuge here, adding a romantic layer to the stark landscape.
- Magic Hill – The illusion works because the surrounding terrain creates a false horizon; it’s a favourite stop for quick photos.
- Barytes Mill Ruins – While the mill is no longer operational, the remaining walls and a few pieces of machinery give a sense of the noisy, steam‑driven past.
Getting There
The Gleniff Horseshoe is most easily reached by car via the N15 from Sligo town (approximately 30 minutes). Public transport options are limited; the nearest bus stop is in Sligo, so a private vehicle or a guided tour is recommended for most visitors.
Practical Information
- Starting point & parking: Gleniff Barytes Mill Site (free, marked on Google Maps). The car‑park is the main gateway for both the drive and the walks.
- Access: The loop is single‑lane; give way to oncoming traffic and watch for sheep that may wander onto the road.
- Trail marking: The 9.1 km Benwiskin Trail is clearly sign‑posted from the car‑park. The longer 13.6 km route is indicated at St Brigid’s Church.
- Facilities: No permanent facilities at the mill site; bring water, snacks and appropriate footwear.
- Safety: The cave climb is hazardous and on private land – view from a distance. Weather can change quickly in the mountains; carry a waterproof layer.
- Best time to visit: Late spring to early autumn for clear views of Donegal Bay; early morning or late afternoon provide softer light for photography.
- Dog‑friendly: Dogs are allowed on the roads and trails but should be kept under control, especially around livestock.
Enjoy the blend of natural grandeur, industrial archaeology and Irish legend that makes the Gleniff Horseshoe and Barytes Mill Site a memorable destination in County Sligo.