These types of fortifications were constructed during the Iron Age, typically between 500 BC and 400 AD, when communities chose naturally defensible positions along the coast and enhanced them with banks, ditches, and ramparts across the landward approach. The strategic placement allowed inhabitants to monitor sea traffic whilst the steep cliffs provided natural protection on multiple sides, requiring defensive earthworks only where the promontory connected to the mainland.

Promontory forts like Málainn Mhóir offer fascinating glimpses into how Iron Age communities adapted to coastal living, combining natural geography with human engineering to create secure settlements. These sites often served multiple purposes; as defensive strongholds, trading posts, and centres of local power where chieftains could control maritime routes and demonstrate their authority through the impressive earthworks that still mark the landscape today.