Looking up to O'Briens Castle inside Dún Formna       Dún Formna - surrounds 14th Century castle
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The Dúns of Aran:

DÚN  Formna
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Inis Oírr
Dún Formna southern walls
Dún Formna west wall

Dún Formna - top view of northern wall

Dún Formna is the only recognised Dún on Inis Oírr, the smallest and most easterly of the Aran Islands. Oírr being derived from Irish for 'east'.

Today it surrounds the 14th century O'Briens Castle which is tall and appears to dominate the old fort. Dún Formna has only one wall and no terracing. This is unusal and makes it the only one of the forts on the Aran Islands without a terraced wall. Another distinguising feature is that the the wall is not high when seen from the interior and appears more like a retaining wall.

Perhaps th fort was not actually a Dún like the others but more like the Dúns found in Co. Clare which are usually constructed of one wall with no terracing. Eexcavations may uncover terracing and walls below ground in the enclosure? However, to date, only two of the Aran Forts have been excavated, Dún Aengus and Dún Eoghanacht. It may also be possible that the current wall was reduced in size at the time the castle was built.


Number of enclosures: 1 (surrounding O'Briens castle)
Enclosure wall height: 3m
No terracing.
Chevaux de frise: None
Entrance location: N



Dún Formna entrance to castle and Dún