A cairnfield is a group of two or more piles of stone (clearance cairns) resulting wholly or partly from the clearance of clitter or lose bedrock brought to the surface by cultivation, in prepration for, or as a result of, agricultural activities. The shape and size of clearance cairns within a cairnfield varies greatly within and between examples, as too does their arrangement. Burial monuments of various classes (eg. round barrows, ring cairns) may form components of cairnfields, and, conversely, clearance cairns within cairnfields were occasionally used for the deposition of burials.
Most cairnfields are situated in upland areas, but there is no reason to suppose that examples may not be identified on lower ground where stone presents a constraint on agricultural practices. It may also be noted that in some areas the construction of other classes of monuments (eg. walls, banks etc.) provided a suitable means of disposing of material collected from field surfaces without recourse to the construction of clearance cairns.
Cairnfields can on occasions be confused with various other classes of monument, notably round barrow cemeteries and groups of round barrows stone hut circles, ring cairns, or burnt mounds. Distinguishing between these can be difficult, but in general round barrows are larger, more regular, and may contain visible traces of a cist or kerb; stone hut circles have distinct entrances; ring cairns have a hollow centre; and burnt mounds contain a high proportion of fire-crazed stones of rather smaller size than appear in the average clearance cairns within cairnfields. Natural deposits such as morains can also on occasion look rather similar to groups of clearance cairns, but thier context, postion and regular form usually betrays their origin.
Specifically excluded from the definition of cairnfields are single isolated cairns, since these can be anything from a marker beside a footpath to a round barrow, and large piles of stones resulting from the clearance of clitter and earthfast boulders using heavy machinery and lifting gear. These last mentioned sites are mostly of very recent origin, and can be easily identified by the fact that they contain stones that could not have been lifted by one or two people.