A midden is essentially a refuse heap, the accumulated shells, bones, charcoal, and domestic debris left behind by communities who ate, worked, and died in one place over generations. What looks like rubbish to the untrained eye is, to an archaeologist, a precisely layered archive of diet, season, trade, and daily habit.

Middens of this kind are found at intervals along the western Irish coastline, many of them associated with prehistoric or early historic settlement. Shell middens in particular tend to cluster near inlets, beaches, and estuaries where shellfish were gathered, and they can represent activity spanning centuries or even millennia. The Sligo coastline and its hinterland have a long record of human occupation stretching back into the Mesolithic period, and a site like this one at Culleenduff, even without excavation, signals the presence of people making sustained use of local marine and terrestrial resources. The townland name itself, from the Irish, suggests a particular kind of landscape, and the presence of a formally recorded midden here indicates that someone, at some point in the archaeological record, identified visible or surface evidence of this kind of deposit.