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The search for the Viking longphort of Linn Duachaill

Eamonn P. Kelly


Viking activity in Co. Louth is documented in the Irish annals from the 820s and the foundation of a permanent settlement on the coast at Linn Duachaill is recorded in the year 841, the same year as the longphort of Dublin was established. For fifty years the longphort of Linn Duachaill was an important base from which raids were launched into the Irish interior and on Britain. In 891 the Vikings were expelled by the local Irish, however, after two decades they returned and Linn Duachaill appears to have been used as a base until around 927 when the fleet departed.
In its early phase Linn Duachaill seems to have rivalled Dublin as a Viking base on the east coast of Ireland. However, its location was not apparently favourable for the development of a town and it was eclipsed later by Dublin and finally abandoned.

The Research Group

The precise location of the longphort of Linn Duachaill has been a matter of speculation by antiquarians, archaeologists and historians since at least the middle of the 18th century. In 2004 Eamonn P. Kelly, Micheál McKeown and Dr. Mark Clinton formed a research group with the aim of identifying the site.

Placename evidence

Placename evidence suggested that Linn Duachaill was located somewhere in the townland of Linns, just north of the village of Annagassan.


The townland is bounded on one side by the sea and on the other by the river Glyde and its confluence with the river Dee, effectively forming a steep-sided peninsula. The high point of the peninsula is at the southern end above the confluence of the rivers. Here there is a D-shaped  earthwork known as Lis na Rann that some scholars believed may have been the Viking fortification referred to in the annals as Linn Duachaill. However, the earthwork is only 80m x 35m in internal extent which, by comparison with longphort sites such as Dunrally, Co. Laois; Knoxspark, Co. Sligo and Woodstown, Co. Waterford, seemed too small for a site of such historical importance. Moreover, Lis na Rann is located at too high an elevation on the steep river bank to have served as a fortress that could protect a Viking fleet. However, the research group considered it possible that Lis na Rann may have been part of a larger Viking fortification, functioning possibly as a strong point or citadel.
It was considered likely that the longphort would have been located within the tidal limit of the river Glyde, which extends as far as a weir on the boundary of the townland of Linns. It was also considered essential that the elevation of the riverbank should be low enough to allow for ships to be taken ashore or launched. These topographical factors led to attention being drawn to an area of low elevation to the south of the weir.

Previous Archaeological finds from Linn Duachaill

Further research revealed that archaeological objects were found in the past in the low-lying area, including two items of fine metalwork of Irish type, probably from ecclesiastical objects of 8th-9th century date. These have the appearance of having been broken off from ecclesiastical objects and their character is therefore similar to items of Irish metalwork found in Viking graves in Norway and at Kilmainham / Islandbridge, Dublin. Similar objects were also found at Woodstown, Co. Waterford and Knoxspark, Co. Sligo.
Such material has also turned up in association with Viking hack-silver and could therefore be regarded as evidence of both raiding and trading by Vikings in Ireland. Also found in the same area as the two pieces of decorated metalwork was a hone stone of Viking type and fragments of human skeletons, probably from ploughed-out graves.
During the 19th century, dredging of the river Glyde revealed a number of archaeological objects including an antler comb and an elaborate Irish decorated bucket of a type that has turned up in Viking contexts in Scandinavia. The precise find places were not recorded but they appeared to be somewhere in the vicinity of the weir. Dredged finds from the river Dee included a Viking axe and an iron slave chain that may be evidence of Viking slave raids upriver from Linn Duachaill.

Geophysical survey

On the basis of all this evidence it was concluded that the best prospects for finding traces of Viking activity was the low-lying area on the riverbank south of the weir. To test this belief, geophysical surveys were undertaken by Target Geophysics, financed by the County Museum, Dundalk.  These revealed evidence for intensive archaeological activity that appeared to be contained to the south of a ditch that ran from the river Glyde to the sea, cutting-off the peninsula, and which had the appearance of having been part of a defensive rampart. However, at this stage it was not possible to be certain that the activity indicated by the geophysical results was of Viking Age date.

Field-walk, 2008.

In order to obtain further indications as to the age of the features, an organised field-walk was undertaken when the field was ploughed in 2008. Micheál McKeown organised and directed this on behalf of the research group.
The pattern of distribution of material was interesting. Flint and marine derived midden material suggesting later Mesolithic Activity was recovered on high ground close to the sea shore. On the lower ground close to the river, flints were not common and midden material, which was present, especially in one location, was mainly animal bone that had been chopped up into quite small pieces. Unlike isolated animal bones scattered across the ploughed field, none of these contained saw marks and appeared to be ancient food debris.
Animal bones with saw marks found further away from the river appear to have been introduced with post medieval midden material used as fertiliser. This was also the likely source of most of the post medieval pottery found scattered across the field. Significantly, modern material was not present in any significant amount in the area close to the river where the geophysical survey showed the greatest density of archaeological features to occur. Neither was slate or brick present as might be expected if the features represented post medieval buildings or activity.


All of the indications were that a key area of the longphort of Linn Duachaill had been located; however to confirm this belief it remained necessary to undertake trial excavation of a number of features in order to obtain evidence of their age and function.