These coastal fortifications, built on naturally defensible headlands jutting into the sea, were once common throughout Ireland's Atlantic shores. The Dunaff example represents a type of monument that cleverly utilised the landscape itself as part of its defensive strategy, with steep cliffs providing natural protection on multiple sides whilst earthen banks and ditches secured the landward approach.

Promontory forts like the one at Dunaff likely date from the Iron Age through to the early medieval period, though without excavation, precise dating remains elusive. These sites served multiple purposes; as defensive strongholds, centres of trade, and symbols of power for local chiefs who controlled strategic coastal locations. The fort's position would have offered commanding views over the surrounding seascape, allowing its inhabitants to monitor maritime traffic and potentially control access to nearby harbours or landing places.