A field system, in archaeological terms, refers to the surviving boundaries, walls, banks, or ditches that ancient and medieval communities laid out to divide and manage agricultural land. These patterns can endure for centuries, sometimes millennia, long after the people who made them are gone, fossilised into the landscape in ways that aerial photography or a careful walk across rough ground can suddenly make legible.

Field systems of this kind are found across Ireland and can date from the Bronze Age onwards, though many in the west of the country are associated with pre-Famine settlement and land use. What makes any individual example worth attention is usually its state of preservation and what it can suggest about how a particular community understood and worked its territory, laying out plots for tillage, grazing, or subdivision among households. Kilcooly, a townland in Galway, is recorded as the location of one such system, though the specifics of its date, extent, and character remain, for now, incompletely documented in the public record.