Banner: Knocknarea at Sunset.
Looking up into the massive mouth of Diarmuid and Grainne's cave.
Looking up into the massive mouth of Diarmuid and Grainne's cave by the Cliffs of Annacuna at the back of the Gleniff Horseshoe. This is one of the the highest caves in Ireland.

Diarmuid and Grainne's Cave

Diarmuid and Grainne's cave is located above the cliffs of Annacuna at the back of the Gleniff Horseshoe, the spectacular glacial valley behind Benwisken. This is one of the highest caves in Ireland, with one of the widest mouths, and has fabulous views out across the valley to the northwest. The cave and the surrounding land is privately owned. Access to the cave is difficult, and the landowners prefer people to look at the cave from below. Always seek the owners and ask for permission before climbing to the cave.

Diarmuid and Grainne's cave
The mouth of Diarmuid and Grainne's cave is massive archway of hard Dartry limestone.

I visited the cave for the first time in January 2011. The cave is a steep climb, straight up for about 400 meters from the old national school. We scrambled up the steep mountain side following sheep trails, and found the going quite difficult. The last part, just before you get to the cave has flimsy ropes attached. We also found it dangerous for the people following after us, as any little stone or rock that gets disloged goes whizzing down the hill, gathering momentum as they go.

mountain rescue
A successful mountain rescue operation took place at the cave on Saturday 21 Feb 2015, when a group of students became trapped by icy weather conditions. Photo by Ciaran Davis.

The cave itself is a massive cavern where water worked its way out through the softer limestone during the last iceage, when the glaciers were more that a kilometer thick over the mountains. The retreating glacier gouged out the massive valley and formed the spectacular cliffs and the unique peak of Benwisken. There are several interconnected gallerys in the cave: the opening known as the 'Keyhole' is shown to the left.

There was some evidence of ancient activity in the cave:

The celebrated cavern of Gleniff, in the Co. Sligo, situated high up on the mountain-side, was certainly inhabited in former times. Some rude flint-flakes, and a bronze hatchet now in the collection to the Royal Irish Academy were here found in a mass of stalagmite, and under the present floor of the cavern bones of recent animals were dug up by the late E. T. Hardman.

Pagan Ireland - W. G. Wood-Martin, 1895.

However, like all other caves, it was surely visited during the mesolithic by the roaming tribes of hunter gatherers and was most likely held to be a very sacred place. County Sligo's megalithic complexes are built in areas with caves: Carrowkeel, Kesh Corran and Knocknarea have about 40 caves between them. Megalithic chambers are really artificial caves.

The view from  Diarmuid and Grainne's cave
The view out from Diarmuid and Grainne's cave to the valley floor 300 meters below.

It is possible that court cairns such as Creeveykeel nearby are actually a replica of the Gleniff valley with the chamber at the back of the court representing the sacred cave. That the cave is dedicated to Grainne, a sun goddess makes sense, as the cave opens to the northeast, the direction of the midsummer sunrise.

The Gleniff Cave, Ballintrillick, County Sligo. The Keyhole can be seen up to the left.


The mythology that goes with the Gleniff cave comes from the cycle of stories certering around the great warrior Fionn MacCumhail. Fionn loved this part of the country and often came here with the Fianna to hunt. In one of the tales, Fionn meets his wife Siabh, the deer goddess on Benbulben, where she has escaped from the clutches of an evil druid. The druid recaptures Siabh, and a few years later Fionn finds a child on the mountain: his son Oisin, the Little Fawn. In later tales Oisin goes to Tir na Nog, from the back of Knocknarea and has a whole cycle of adventures of his own.

Ancient Troglodyte Retreat
Ancient Troglodyte Retreat: a passage in the Great Cave of Gleniff. From a photograph taken by Mangnisium light. From Pagan Ireland, W. G. Wood-Martin, 1895.

Diarmuid and Grainne were lovers fleeing the wrath of Fionn: Grainne was supposed to marry the older Fionn but instead ran away with the handsome young warrior Diarmuid. In the 'Pursuit' cycle of tales, the lovers had to sleep in a different place each night, as Fionn and his hunting dogs were always just on their trail.

A fiddle tune in Diarmuid and Grainne's cave.

This is how so many Irish megalithic chambers became called Leabas or beds, for example the Labby Rock by Lough Arrow in south Sligo. After sixteen years Fionn makes his peace with the lovers and they settle down at Grainnemor near the Caves of Kesh Corran. Fionn, who never really forgave them, lures Diarmuid up to Benbulben to go hunting and ensures that he is killed. As with all Irish mythical tales, the story is long, complicated, and often like a soap opera. You can read a full version of the Pursuit here.

Alas, O Diarmuid O'Duibne,
O thou of the white teeth, thou bright and fair one;
Alas for thine own blood upon thy spear,
The blood of thy body hath been shed.

Alas for the deadly flashing tusk of the boar,
Thou hast been sharply, sorely, violently lopped off;
Through the malicious, fickle, treacherous one.

Numbing venom hath entered his wounds,
At Rath Finn he met his death;
The Boar of Benn Gulban with fierceness,
Hath laid low Diarmuid the bright-faced.

Raise ye fairy shouts without gainsaying,
Let Diarmuid of the bright weapons be lifted by you;
To the smooth Brug of the everlasting rocks—
Surely it is we that feel great pity.

The poem above is the lament chanted by Aongus Og over the body of his foster son Diarmuid on top of Benbulben. Aongus then took Diarmuid's body back to Newgrange with him and breathed an aerial life into him, so they could sit and talk and play chess. This is very interesting as Benbulben is one of the sites on the massive energy or Ley line crossing Ireland from Newgrange to Inishmurry island. The line, which is discussed in Michael Poynder's book Pi in the Sky, passed quite close to the cave.

The Cliffs of Annacuna
Looking east to the Cliffs of Annacuna at the back of the Gleniff Horseshoe. Diarmuid and Grainne's cave, one of the highest Irish caves, is in the cliff, top right. The Byrites mines are in the cliffs straight ahead.


Gleniffe Caves are the finest in the whole district. They occur near the summit of the northern edge of the Ben-Bulbin range, overshadowing the deep valley of Gleniffe, and are only reached after a toilsome climb of over 1,200 feet up a very steep grassy slope, followed by a talus of loose stones; then comes a precipitous face of rock some forty feet high, difficult to scale, except by the naked foot of the native guide.

Overcoming this difficulty, and that of a highly-inclined steep above, the toiler reaches the entrance, an immense natural arch about thirty or forty feet high, and fully sixty feet wide. The opening cavern is large, but of no great beauty; and the candles of which a good supply should be taken being lit, the exploration may be commenced.

An opening to left leads into a vast chamber, which we may call the drawing-room. It would be impossible to estimate the size of this great cavity, but sometimes a light flashed through the gloom on a piece of rock fully fifty feet above our heads; and still higher were deeper depths of shade, indicating further recesses.

The extent of the chamber must be very great, but the accumulation of immense blocks of fallen rock from the roof rendered it quite out of the question to make a thorough exploration, unless more than one day be given to the task. These blocks suggest an uncomfortable possibility. What if a piece of roof, weighing some twenty tons or so, should become detached and form the tombstone of the explorer? A pleasant thought, but the chance is far from remote.

As the lights flit around, great depths and abysses are revealed, stalactites hung like petrified bunches of grapes from the roof, and the walls and overhanging ledges exhibit stone "icicles" and massive coatings of stalagmite in every fantastic form that nature can devise.

To the right is a narrow but lofty chamber, the square and solidly-cut walls of which give the idea of an ancient castle keep. Presently the cave contracts and lowers, aud the Gothic gallery is entered, nature simulating very effectively. Close to the entrance is a curious formation of stalagmite, resembling an old-fashioned farm-house chimney, or "ingle-nook," of huge dimensions, at one side of which is a colossal female figure. This being robed, might be considered a Caryatides, but was by acclamation voted to be Lot's wife. Further on, the gallery of Gothic arches became very narrow, and in places very difficult of pas- sage, and somewhat precipitous. It leads us again into the entrance-hall.

We now make for the "Gravel Walk," a fine Gothic gallery, with a beautifully smooth gravelled pathway, some eight feet wide. This passage, which is about 100 feet long, leads from the left of the entrance arch, and winding around for some distance, opens out finally on the face of the cliff, affording a magnificent view of the country to the north-east and east, including Bundoran and the great cliffs of the Donegal coast.

Some little distance from the opening, a "Crumpawn," or steeple-shaped pinnacle, rears itself in solitary grandeur. The guide informed us that some time before, a young lady of the County Sligo scaled this rock, and perched herself on the summit. The position had apparently no charms for any of our party The artist of the parly required a figure in that precise part of the foreground, but an immediate interest in the interior of the cave seemed to be developed by the suggestion. This pinnacle exalts itself over a precipice of about 200 feet, and offers about two feet of solid standing-ground.

The descent is somewhat more rapid than the ascent; in some places, perhaps, inconveniently more so. Those who, like Dr. Johnson, prefer to travel fast, might find a toboggan useful, and might also discover the practical meaning of " accelerating velocity." This process would occupy about five minutes, but those who are not in a particular hurry can conveniently accomplish the journey in about twenty minutes.


A drawing of Benbulben from 1812
A drawing of Benbulben from 1812.