Unlike the vertical wheel most people picture when they think of a watermill, a horizontal mill, sometimes called a tide mill or Norse mill, used a wheel lying flat beneath the millstone, driven directly by a jet of water channelled through a wooden trough or millrace. The design was simple, relatively easy to build, and well suited to the modest streams of the Irish countryside.

The remains at Horeswood were examined by the National Museum of Ireland in 1965, though whatever was recorded at the time has not made its way into the public record in any detail. The site sits in a stream valley, and beyond those bare coordinates, the historical specifics have gone quiet. Horizontal mills in Ireland generally date from the early medieval period, roughly the sixth to the twelfth centuries, and they were often associated with monastic or small farming communities who needed a local means of grinding grain without the engineering demands of a full vertical mill. That the Horeswood example was considered worth investigating at all suggests something survived above or below ground at the time, even if the record since then has grown thin.