It is over 213 metres long, cut into rock in places, and drops to around 4.5 metres deep in certain spots. It is far too deliberate, too precisely excavated, to be a natural feature, yet no mill survives, no wheel, no stonework above ground. What remains is essentially the negative space of a machine that once turned grain into flour, preserved mainly as an earthwork and a local memory.

The site was examined and described by A. T. Lucas in 1953, who noted that the trench runs roughly northeast to southwest and forms the chord of a bend in the stream, a configuration consistent with a mill race, the channel used to divert and direct water onto a mill wheel with enough force to drive it. Lucas recorded both the physical dimensions and the local tradition that a mill once stood here, and on the basis of those together he suggested it may be the site of a horizontal-wheeled mill. The horizontal or Norse mill was one of the earliest mill types used in Ireland, dating back at least to the early medieval period. Unlike the more familiar vertical waterwheel, a horizontal mill used a wheel laid flat beneath the millstone, its paddles struck by a jet of water channelled through a narrow opening. The mills themselves were often modest timber structures and have rarely survived, leaving only their races, if anything at all. A rock-cut channel of this scale points to serious, organised effort, not a temporary or casual arrangement.

The site is defined more by what can be inferred than by what can be seen, and anyone expecting obvious mill machinery or standing remains will find instead a long earthen and rock-cut depression following the curve of a small stream. The interest lies in reading the landscape rather than examining a monument.