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A Summary of the Irish Souterrain



The Irish souterrain is an artificial cavity constructed predominantly underground within the constraints of local geography and geology. A souterrain may take the form of a simple cavity secreted beneath a single flagstone, or as a multi-levelled complex of interconnecting passages and chambers. Often associated with ringforts, souterrains may also occur among ecclesiastical and open settlement locations. Precious little detail is recorded in the annals so knowledge is somewhat limited.  Souterrains are by their very nature discreet, obscure from casual gaze, often today observed as a small shadowy area among the turf. Careful camouflage of their entrances became an integral part of their design giving an ability to preserve its presence as a secret refuge when a settlement came under attack. Many are now collapsed, difficult to locate or even enter. Over millennia their small openings gradually became choked by migrating soil. Close association with the supernatural still surrounds Faerie Forts (ringforts). Such sincere belief slowly decreases as older generations pass. To many the very idea of someone willingly venturing underground fills them with a deep dread with the underworld evoking images of entrapment, death and decay.



Nationwide food production increased significantly during the Early Medieval Period as ploughing became more efficient. Introduction of innovations such as the moldboard plough, with its curved blade allowed previously unproductive heavy soils to finally be cultivated. During ploughing the moldboard plough blade cleverly turned the soil to bury weeds thereby reducing competition with the cereal crops for available nutrients. This led to a food surplus and reduction in infant mortality. It meant that subsistence farmers now had a surplus with which to exchange for hitherto inaccessible items. Prior to the Viking invasion, (795CE), there was no coinage as such as barter and exchange prevailed with cattle and slaves becoming the normal everyday Irish currency. The increasing food surplus gradually increased the Irish population. In doing so some larger farming family groups developed as powerful clans with the more bellicose pursuing even greater wealth, power and status by conducting raids on other settlements. Small raids focused upon driving off cattle while the more serious stole a farmer’s settlement, land, wealth and produce, pressing any survivors into slavery. Minor raids have been suggested as form of a test, a rite of passage for a youth to come of age and enter adulthood. Hostilities were endemic throughout Early Medieval Ireland. The status of the area overlord was based on the possession of cattle and slaves to work the land with the greater their numbers the greater his prestige. Raids continued, the threat increased and steps were taken to elude capture and enslavement.



Academic argument has moderated in recent years with the realization that many entrances into Irish souterrains are so designed that their intended original use could be for no other purpose than to act as a discreet opening to a defensive refuge in which non-combatants may elude an attack.  Some souterrains have larger openings, a feature that may have fueled past argument as a convenient storage facility. Debris adjacent to an entrance can imply interference with its original dimensions converting a site’s original use from refuge to storage. Clues to a souterrains original use may possibly be found within such as sections of passages purposely designed to form a defensive obstacle from which a single non-combatant may stop an invader with a weapon. Alternately, being underground means that a stable temperature is maintained and that offers a cool, dry, dark environment to store surplus crops, dairy produce and valuables.



Souterrains are broadly considered contemporaneous with the Irish Ringfort, constructed, mostly, during the Early Medieval Period, (400CE – 1200CE). Absolute (precise) dating of souterrains remains elusive owing to the predominance of stone in their construction and lack of remains obtained from sealed contexts. Samples taken of oak posts from the collapsed wooden souterrain at Coolcran, Co. Fermanagh returned a date of 822CE +/- 9 CE, (Early Medieval Period). 
Relative (associative) dating of finds often suggest the above period. When excavating Cahercommaun, Carron, Co. Clare, Hugh O’Neill Hencken applied relative dating establishing a period for this high status cashel and its two souterrains by using the silver penannular broach found in Souterrain B, as it closely compared to the designs of 9th century broaches. Excavations at Cush Co. Limerick, conducted by Professor S.P. O’Ríordáin, found within Ringfort No.5 a dry stone souterrain adjacent to several Bronze Age (2200BCE – 500BCE) burials. The souterrain was found beneath a layer of charcoal and burnt remains from an adjacent pyre associated with Burial 1. Dating was based on stratigraphic evidence. Post excavation research eventually placed this particular souterrain, one of several in the area, in the Late Bronze Age (1000BCE–500BCE).



All land is owned by someone, somewhere, even commonage. Permission need be obtained prior to crossing any land to visit any site. Searching for a specific landowner often brings the seeker into contact with, at the very least, neighbouring farmers, all of whom do appreciate the effort taken by a stranger. Such enquiries have led to countless cups of tea and cake in cosy farm kitchens exchanging craic, during which far more information is imparted regarding the surrounding countryside than can ever be accumulated over months of prospecting the landscape on foot. 



The Irish National Monuments Act prohibits any interference or excavation of any recorded or suspected archaeological site unless the excavation is conducted by a Director licensed and registered with the Department of Culture, Heritage and the Gaeltacht. The deployment of a metal detector for the purposes of searching for archaeological remains, items or artefacts is illegal. 

In short, if a choked souterrain is encountered the area may be recorded, surveyed and photos taken, but the site may not be disturbed.

Pat Cronin, May 2018

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