A cashel is simply the stone-built equivalent of the more familiar earthen ringfort, a roughly circular enclosure used in early medieval Ireland, most likely as a defended farmstead for a family of some local standing. While earthen ringforts were constructed from banked soil and ditches, cashels were built where stone was plentiful, their dry-stone walls serving the same purpose of enclosing a household and its animals against both the elements and opportunistic neighbours.

Ringforts of both kinds are among the most numerous archaeological monuments surviving in Ireland, with estimates suggesting somewhere in the region of forty to fifty thousand once existed across the island. The majority date to the period between roughly the sixth and twelfth centuries, though some continued in use or were adapted long after. In the west of Ireland, and particularly across County Mayo, cashels are a familiar feature of the older farmed landscape, often sitting at field edges or on slightly elevated ground where their builders could keep watch over surrounding territory. The townland name Greyfield offers little immediate clue to the site's history, but the survival of the monument itself suggests it escaped the kind of intensive land clearance and agricultural improvement that destroyed so many comparable sites elsewhere.