The name itself is arresting: Knocknashammer derives from the Irish, and townland names in this part of Connacht frequently preserve traces of older land use, local legend, or the names of families long since dispersed. The earthwork, whatever its precise form, belongs to a category of monument that could encompass anything from a prehistoric enclosure or ringfort to a post-medieval field boundary or the remnant of a much older ceremonial site. Without further documentation, the feature retains a quiet ambiguity that is, in its own way, characteristic of the Irish landscape, where the ground holds more than it readily gives away.