The enclosure is oval in shape, measuring roughly 46 metres north to south and 32 metres east to west, and its earthen bank still stands to about a metre in height. Modern stone field fences have been built across its western and north-eastern edges, a gate now marks the old gap on the west side, and a further fence bisects the interior from east to west. Agriculture has not so much erased this feature as grown up around and through it.

Enclosures of this kind, broadly circular or oval areas defined by an earthen bank, are among the most common archaeological monument types in Ireland, and are often associated with early medieval settlement, though their precise dates and functions vary considerably. What makes the Killour example quietly interesting is its relationship to a nearby souterrain, an underground stone-lined passage typically associated with early medieval farmsteads, possibly used for food storage or as a place of refuge. The souterrain lies to the east, towards higher ground, and the two features together suggest that this modest corner of Mayo was once a more organised and inhabited landscape than the present silage pit might imply.