Ireland's Man-made Structures

Prehistoric / Ancient

Carrowkeel, Co. Sligo, a neolithic hilltop cemetery (Photo – The Blessed Isle, an interesting blog).

Radiocarbon evidence indicates that some of the megalithic structures in the County Sligo area date from c. 5400 BC.  Croaghaun in the Ox Mountains has produced a date going back as far as 5600 BC from samples of charcoal found in the central chamber. Samples taken from a stone socket in Primrose Grange Tomb 1 have yielded a date of 6400 BC. Taken on their own, these extremely early dates for megalithic activity in Ireland are sure to draw scepticism, it should be noted by the sceptic however, that five dates from three different tombs point to activity on these sites between 6400 and 4600 BC, far earlier than anywhere else in Europe. These very early dates seem to indicate that the practice of constructing megalithic monuments in Ireland started on the west coast.


Cairns are  artificially constructed heap of stones. Queen Maeve’s Grave on top of Knocknarea (near Sligo) is a prime example. Here we actually do not know whether the cairn is solid or a tomb.

Dolmens – see Tombs


Enclosures are. generally. anything that cannot be identified and encloses a part of the landscape  – i.e. a man-made structure we do not know a lot about. It could have been erected for domestic, agricultural, ceremonial or even defensive / military purposes (although usually lacking the appropriate ditch outside the walls). Enclosures also tend to be found in conjunction with tombs and/or henges. Navan Fort (near Armagh) seems to have been a ceremonial enclosure, as were some earthworks on the Hill of Tara.



Ringforts include any roughly circular fortification from prehistoric times is generally called a ringfort – raths, cashels, promontory forts and cashels being examples. The distinction between (defensive) ringforts and (ceremonial) enclosures is not always easy as both make use of walls and ditches. A fort will usually have the ditch outside the wall to make things harder for attacking enemies.


Raths are ringforts consisting mainly of a ditch and an earth wall – the last usually topped by a wooden palisade.




Cashels  are basically ringforts built mainly of stone. Often this takes the form of an earthen enclosure with and outer ditch and an inner earth-wall, topped by an additional stone-wall. The latter could be either a basic breast-high structure or a massive construction.


Promontory Forts are ringforts located on promontories, one side of the “ring” often consisting of sheer cliffs. The Aran Islands do have the most spectacular forts of this kind, especially Dun Aonghasa.


Crannógs are ringforts on small islands near a shore – the fort is identical in size to the island, both are often connected to the mainland by a narrow bridge or causeway. The island could be either natural or artificially created (or expanded). As a rule the more circular an island the more likely it is to be artificial.


Fairy forts /  Rings / Hills – After a few millennia of existence the passage tombs and similar buildings were re-interpreted as gates to the Otherworld and dwelling places of fairies. This may in part be a reflection of the mysterious symbols carved into the stones and artefacts that could be found in or near tombs.

Henge –

Ley-Lines – “The old straight track” can be found in Ireland too – ley-hunters have identified several good examples. But as the science, history and even existence of ley-lines is disputed the field is wide open for interpretation. Basically ley-lines are alignments connecting important places, forming a grid on the landscape. As these alignments are far less supported by hard evidence than the astronomical or solar alignment of an individual site a lot of ley-hunting quickly descends into mere speculation.



Court Tombs first appearing around 3,500 BC these are (usually) half-moon shaped tombs with a pronounced “courtyard” in front of the entrance. The courtyard was supposedly used for rituals, either during burials or at festive occasions.


Wedge tombs are very similar to court tombs – actually they look like truncated court tombs. Leading to the impression of a “wedge”, hence the name. Popular from 2,000 BC


Passage tombs are round tombs with a definitely identifiable passage leading from an entrance to the burial chamber. Most popular around 3,100 BC. One of the best-known passage tombs in the world is Newgrange, though nearby Knowth actually has two passages. Tombs like these two or the main tombs at Loughcrew often have spectacular astronomical, especially solar alignments. Geographical alignments seem obvious at Carrowmore.


Portal tombs are constructed out of three (sometimes more) massive standing stones, bearing an even more massive slab. Looking like a portal. The covering slab can be up to 100 tons in weight and forms the roof of a chamber. Most portal tombs were erected between 3,000 and 2,000 BC.


Dolmens are the uncovered remains of portal tombs. The most famous Irish dolmen is Poulnabrone in the Burren.


Heroes’ Graves and Beds are partly destroyed and uncovered tombs, open chambers and dolmens were often re-interpreted in the light of Celtic mythology – mostly the Fianna cycle. Ireland abounds with structures said to be the (often final) resting places of heroes and lovers.

Souterrains are cellars, underground passages created near settlements and believed to have been used as storage areas, hiding places and escape routes. Some appear near tombs such as Dowth (near Bru na Boinne), leading to considerable confusion amongst antiquarians.

Significant Stones


Standing Stones are basically monoliths placed on their own or forming part of a henge or circle. In conjunction with tombs, enclosures or natural features even solitary standing stones may have astronomical, solar or geographical alignments. Some standing stones were erected for purely practical purposes, though – as scratching posts for cattle.


Ogham-Stones are Standing stones bearing inscriptions in the ancient Ogham-system, a special written language mainly used in Ireland. Unfortunately the inscriptions are generally very short and not very interesting. Ogham stones form a “bridge” between pre-historic and early Christian times.


Menhirs – 


Stone Circles

The Lewis Glucksman Gallery, UCC, inaugurated in 2004.

(More soon!)

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