It is classified as a ruin, yet for most of its documented history it was anything but; the building was still described as a functioning corn mill as recently as the 1925 edition of the Ordnance Survey six-inch map, which makes its current stillness feel relatively recent.

The site has a remarkably long paper trail for a structure of its kind. Both the Down Survey map of 1654 to 1658 and the Civil Survey of 1654 to 1655 record a mill at Dungulph, placing it among the earlier post-medieval industrial sites in the county. The Down Survey, commissioned under Cromwellian administration to map forfeited Irish lands, and the Civil Survey, a companion census of land ownership and value, together offer a rare twin confirmation of the mill's existence in the mid-seventeenth century. By 1839, when the first edition of the Ordnance Survey six-inch map was published, a flour mill appeared just to the north-west of Dungulph Castle, though the ruined corn mill at the southern end of the townland is considered the more likely continuation of the earlier site. The standing structure itself is probably nineteenth century in date, suggesting the mill was rebuilt at some point after the earlier building fell out of use or fell down entirely, before being recorded again as operational in the early twentieth century. It is now used as a store.