This commanding fortification sits at 661 feet above sea level, offering sweeping views across the Limerick plains. The monument consists of a central mound approximately 10.4 metres high, with a level summit measuring 16.2 metres across. This central feature is surrounded by a series of three concentric banks, or valla, with fosses between them; though time and development have taken their toll, particularly on the northern side where the enclosing banks were levelled to make way for the adjacent Fair Green.

The earthwork’s impressive scale becomes clear when examining its dimensions: the inner vallum rises 4.9 metres high and spans 7.8 metres at its base, whilst the middle vallum stands 3.2 metres tall with a 4.7-metre base width. The outermost vallum, though largely removed over the centuries, originally measured 1.6 metres in height. The entire monument once stretched just over 101 metres from north to south. Historical maps from the 19th century tracked its changing appearance; the 1840 Ordnance Survey shows it as a circular area with two banks and a trigonometry station at its centre, whilst by 1897 it was depicted with three banks and the central mound clearly marked.

The site holds particular significance in early Irish literature, appearing in the Book of Rights (Leabhar na gCeart) in a poem attributed to St. Benean from the fifth century. The verse speaks of “Drumfinghin of the wood, with it Treada na Righ,” identifying it as a triple-banked fort of kings. Scholar Thomas Westropp confirmed in 1917 that this reference “unmistakeably” refers to Kilfinnan, cementing the earthwork’s place in Ireland’s royal heritage. A standing stone sits immediately to the southwest, adding another layer of archaeological interest to this remarkable hilltop fortress that has watched over the Limerick countryside for well over a millennium.