This bivallate (double walled) fort stands near the highest point of Inis Mór. A concentration of other settlement sites (cashel, stone enclosures and house sites) occurs in the immediate vicinity. Without excavation it is not possible to say for certain when Dún Eochla was built. The remains visible today suggest that it belongs to the cashel class and this would place its construction sometime in the period 550 - 800AD. It is possible however that the present fort replaced an earlier mounment but again only excavation could ascertain this. No trace of any houses are evident today in the interior - the round structure may have been a signal station associated with the nearby lighthouse.