SECTION 1 : Introduction
SECTION 2 : Multi-period sites
SECTION 3 : Mesolithic
SECTION 4 : Neolithic Settlement
SECTION 5 : Megalithic tombs and Neolithic burial practices
SECTION 6 : Bronze Age Occupation Sites
SECTION 7 : Bronze Age burial practices
SECTION 8 : Iron Age
SECTION 9 : Iron Age burial practices
SECTION 10 : Royal sites
SECTION 11 : Western stone forts
SECTION 12 : Early Medieval Period - Christianity
SECTION 13 : Ringforts
SECTION 14 : Crannógs
SECTION 15 : Medieval Dublin
SECTION 16 : Late Medieval Period
SECTION 17 : Anglo-Norman Towns
SECTION 18 : Anglo-Norman Fortifications


These stone ringforts or cashels are known throughout Ireland but with a specific concentration in the west. The majority, including Dún Eoghanachta discussed below, were probably constructed as homesteads from 500-800AD, however some also produced evidence for prehistoric activity on these sites with extensive remodelling and rebuilding over extended periods of time. Similar to ringforts, the size of the stone forts and the number of enclosing elements varies. Common architectural features include terracing of the walls, passages/chambers within the walls, stone steps and at least four examples have a chevaux de frise for extra defence. Some stone forts, such as Dún Aonghasa, appear to have had their origins in the Late Bronze Age and Iron Age hillforts and appear to represent a period of social unrest and strengthening of tribal borders. Excavations at several hillforts have suggested that they may have been occupied by elite groups that had broader social and ritual functions. Many were reused in the Early Historic period as royal centres, probably deriving their wealth from controlling some sea trade.

11.1 : Dún Aonghasa, Inis Mór, Co. Galway 92E0102

Site location: NGR 08176/20975           SMR GA110-039---

Claire Cotter

Fig.11.1.1: Location map of Dún Aonghasa, Inis Mór, Co. Galway [OSI]

Plate 11.1.1: Aerial view looking north, Dún Aonghasa, Inis Mór, Co. Galway
[Con Brogan]

Fig.11.1.2: Main structural elements, Dún Aonghasa, Inis Mór, Co. Galway
[Claire Cotter]

The fort of Dún Aonghasa is perched at the edge of sheer sea cliffs on the SW side of Inis Mór in the Aran Islands (Fig. 11.1.1; Plate 11.1.1). It is an extensive cliff-top fort that is roughly D-shaped in plan and encloses 5.7 hectares. The site is defended by three principal walls and a substantial chevaux de frise which lies outside the middle wall (Fig 11.1.2). The work on Dún Aonghasa was carried out over four seasons from 1992-5, as part of the Western Stone Forts project of the Discovery Programme. The primary objectives of the excavation were to investigate whether any archaeological deposits were preserved in situ and to establish whether such deposits in turn might provide any dating of the extant structural elements.

During excavation (Fig 11.1.3) three main phases of activity were revealed and some pre-enclosure activity was also detected by radiocarbon dating food remains from the inner enclosure to 1500 BC.

11.1.3: Plan of excavated features, Dún Aonghasa, Inis Mór, Co. Galway
[Claire Cotter]

Around 1100 BC (Phase 1) the first enclosure was erected by piling rubble against large upright stones. A number of structures were detected and although poorly preserved it appeared they were constructed of timber with the main posts set on stone foundations.

The best preserved structure uncovered was a roughly circular hut (Hut 1), 4.8m in diameter the walls of which extended under the inner enclosure wall. The interior of the hut was filled with a midden type deposit including pottery, a clay mould fragment for a spearhead and a bone spindle whorl. The date of this hut is however very uncertain and more recently it is thought that it is not Late Bronze Age in date, though it clearly predates the inner enclosure.

East of the hut a possibly contemporary stone-lined trough and stone hearth was cut into the midden layer and the hearth yielded a date of 752-392 Cal. BC. The foundations of a second hut and the remains of a stone lined pit were discovered to the east of Hut 1. Faunal remains recovered included sheep, cattle, fish, limpets and periwinkle shells. Some barley grains and a number of saddle querns were also uncovered along with large pottery vessels. Stone axes, hammers and whetstones, bone pins and needles and bone, stone, pumice, glass and amber beads were all retrieved. A number of clay moulds used to cast bronze objects suggested on-site manufacturing and four perforated bronze rings found together near the cliff edge inside the fort may have been a deliberate deposit. A large fire and dense concentration of animal bone was detected in the inner enclosure and may have represented a feasting area. A large quarried hollow in the bedrock at the NE corner contained an infant burial.

After about 500 BC there was a decrease in activity at the fort and the second phase of building may have been prompted by the same event which caused the construction of a number of coastal promontory forts along the western coast of Ireland. The triple wall defences were probably built along the western side of fort during this phase and the chevaux de frise was erected. The remains of a structure and some pits in the middle enclosure were also excavated.

The final phase (Phase 3) may be dated to 500-900 AD based on comparison with similar forts. This saw the inner wall reinforced and heightened. Some contemporary occupation levels were uncovered but it did not appear to form a major settlement.

The excavation of Dún Aonghasa was vital in gaining a deeper understanding of the western stone forts and particularly the density of sites on the Aran Islands. It provided evidence for early activity and long term occupation, with the material culture suggested a strong link to the mainland and a certain level of wealth.


Cotter, C. 1993  ‘Dun Aonghasa’, Kilmurvey, Inismór’. In I. Bennett (ed.), Excavations 1992. Wordwell Ltd., Bray. 31-32.

Cotter, C. 1993. ‘Western Stone Fort Project: Interim report’. Discovery Programme Reports 2: Project results 1993. Royal Irish Academy, Dublin, 1-11.

Cotter, C. 1994  ‘Dun Aonghasa, Kilmurvey, Inismór’. In I. Bennett (ed.),  Excavations 1993. Wordwell Ltd., Bray, 39-40.

Cotter, C. 1994 ‘Western Stone Fort Project: Interim report’. Discovery Programme Reports 4: Project results and reports 1994. Royal Irish Academy, Dublin, 1-14.

Cotter, C. 1995  ‘Dun Aonghasa, Kilmurvey, Inis Mór’. In I. Bennett (ed.),  Excavations 1994. Wordwell Ltd., Bray, 39-40.

Cotter, C. 1996. ‘Dun Aonghasa, Kilmurvey, Inis Mór’. In I. Bennett (ed.),  Excavations 1995. Wordwell Ltd., Bray.

11.2 : Dún Eoghanachta, Inis Mór, Co. Galway  95E0136

Site location: NGR 81160/21137            SMR GA110-020---

Claire Cotter

Fig.11.2.1: Location map of Dún Eoghanachta, Inis Mór, Co. Galway [OSI]

The fort at Dún Eoghanachta stands on a shoulder of level ground bounded along the south, east and west by rising broken terrain (Fig. 11.2.1; Plate 11.2.1). This circular cashel was restored in the nineteenth century and consists of a massive drystone rampart with two terraces and interconnecting steps. It is situated 1.5km NW of Dún Aonghasa. The site was selected for excavation because of its architectural similarity to Dún Aonghasa and because its simple plan and small size suggested that it was likely to be a single-period site and would therefore provide an accurate date for its construction. The excavation was carried out over five weeks in 1995 and was funded by the Discovery Programme as part of the Western Stone Forts Project.

Plate 11.2.1: Aerial view, Dún Eoghanachta, Inis Mór, Co. Galway
[Claire Cotter]

This univallate stone fort measures 26m internal diameter. The entrance is in the east sector and consists of a faced featureless opening. A terrace runs along the inner face of the wall, with five sets of steps leading from the ground to the terrace and a further five sets of steps leading from the terrace to the top of the wall. The interior is level with a large expanse of bedrock towards the centre. Three structures stand in the western sector. The largest (Structure C) is rectangular in plan with a doorway in the north wall. The west wall abuts back against the lower terrace of the fort. Two lintelled recesses in this wall may have been cupboards or fireplaces. This house may be medieval or later in date. Structure B is conjoined to the south side of Structure C and also rectangular in plan. It consists of a lean-to abutting the fort wall and the structure partly obstructs a set of steps in the rampart. Structure A also abuts against the west wall of the fort and is irregular in plan. The north wall and the doorway in the east wall are partly obscured by a build-up of rubble.

Half the interior of Structure C and a 1m wide strip on the corresponding sector of the exterior were investigated as well as were half the interior of Structure A and a 1m strip along the exterior of its south wall. Similar deposits were uncovered in all cuttings. The earliest deposits were midden dumps that produced an iron ring-headed pin, an amber bead and a slotted-and–pointed iron tool that were probably contemporary with the construction of the fort. Spreads of darker charcoal-rich soil may represent the remains of hearths. Two hollows in the bedrock outside the east wall of Structure C can be interpreted as rubbish pits and contained cattle, pig, sheep and red deer bones. No occupation surfaces for Structures A and C survived. A flat slab on the ground surface in Structure C may be part of a hearth. An Edward I coin was recovered from Structure A represents some activity at the site in the thirteenth century. Overall this limited excavation pointed to a date in the second half of the first millennium AD for the construction of the fort.

This excavation was an important investigation of a large secular stone building which was occupied prior the coming of the Normans and may also have been a royal site.


Cotter, C. 1996  ‘Dún Eoghanachta, Eoghanacht, Inis Mór’, In I. Bennett (ed.),  Excavations 1995. Wordwell Ltd., Bray.

11.1 : Dún Aonghasa, Inis Mór, Co. Galway 92E0102
11.2 : Dún Eoghanachta, Inis Mór, Co. Galway  95E0136