A cist is a small stone-lined burial box, typically dating from the Bronze Age, constructed by setting flat slabs on edge to form a rectangular chamber and then capping it with a covering stone. They were built to hold the dead, sometimes a single crouched burial, sometimes cremated remains, and they survive across Ireland in varying states of completeness, some still sealed, others long since disturbed by ploughing, construction, or simple curiosity across the centuries.

Keel itself sits on the southern shore of Achill, a place where human activity stretches back thousands of years and where the Atlantic has always shaped the conditions of settlement. The presence of a cist here fits a broader pattern of prehistoric funerary activity along Ireland's western seaboard, where Bronze Age communities, roughly spanning from around 2500 to 500 BC, used these modest stone constructions to mark and contain their dead. The specific details of this particular cist, its dimensions, its current condition, whether it was excavated or found intact, remain undocumented in what is publicly available at present.