The site is a rath, a type of enclosed farmstead or settlement built during early medieval Ireland, consisting of a raised circular bank and an outer ditch enclosing a central living area. This one, roughly 38.5 metres in diameter, sits on slightly elevated ground in reclaimed pasture at the lower eastern end of the valley, its bank still standing between 1.7 and 2.3 metres high on the exterior. It is well preserved, though heavily overgrown, and badgers have worked their way into the earthwork in several places, which is not unusual for ringforts left undisturbed for long periods.

The name is what gives the site its particular colour. Writing in 1901, the antiquarian T. J. Westropp drew on the medieval Irish manuscript known as the Book of Ballymote to suggest that Doontorpa may take its name from a certain Torptha, or Torpa, who was chief of the Corcomroes around A.D. 750, or from a contemporary prince of Thomond. Torpa, according to the same source, was the son of Cermad and grandson of Dima, a man who in A.D. 636 had claimed the kingship of Munster from Failbe Flan. Whether or not the rath itself dates to Torpa's lifetime, the name alone threads the site into a genealogy of early Irish kingship that stretches back to the turbulent politics of seventh-century Munster. The site appears by name on both the 1840 and 1916 editions of the Ordnance Survey six-inch map, and an earlier twenty-five-inch edition indicated an additional outer bank running from the south to the north-west, though a 1999 inspection found no trace of it remaining on the ground.