A midden is, at its simplest, a refuse heap, the accumulated shells, bones, ash, and discarded material of people who once ate, worked, and lived in a place. That description makes them sound mundane, but middens are among the most informative archaeological deposits known. The compacted layers within them can preserve organic material across thousands of years, and the contents read almost like a ledger of daily life, recording what people ate, what seasons they gathered food, and how their habits shifted over time. Ireland's coastline and interior are scattered with such deposits, some dating to the Mesolithic period.

Culleenduff itself is a townland in Sligo, a county whose Atlantic fringe and drumlin country have been inhabited since prehistory. The precise character and date of this particular midden, whether it is coastal or inland, Neolithic or more recent, shell-bearing or bone-rich, remains to be drawn out from the available record. What is certain is that it has been formally recognised as an archaeological monument, a designation that places it within the wider story of how people have occupied and used this corner of the west of Ireland across many generations.