The term refers to a deposit of fire-cracked stones and charcoal-rich soil, typically dark and heat-reddened, left behind by repeated burning activity in prehistoric times. These spreads are closely related to fulachta fiadh, the more widely recognised mound sites associated with ancient cooking, bathing, or industrial processes, though a burnt spread often represents a flatter, less structured version of that same activity, where the debris was not heaped but dispersed across the ground surface.

Burnt spreads of this kind are found across Ireland in considerable numbers, and Kerry is particularly rich in prehistoric landscape features of all sorts. The practice they represent, heating stones in fire and plunging them into water-filled troughs to raise temperatures rapidly, was in use from the Bronze Age onwards, roughly from 2000 BC, and some sites show evidence of use continuing over long periods. The exact character of the Garraundarragh example, its dimensions, its precise date, and the circumstances of its discovery or recording, are not currently available in published form.