At 499 feet above sea level on Silliot Hill in County Kildare, there is a ring barrow whose circular earthen bank is unusually precise: 33 metres in diameter, standing 1.4 metres high and 3.7 metres wide, enclosing a slight internal fosse, which is the shallow ditch typically dug to provide material for raising the surrounding bank. What makes this particular mound more than a curiosity of prehistoric earthwork is the company it may have kept. Scholarship has placed here, on or around this hill in the parish of Carnalway, one of the most significant gatherings in early Irish life.

That gathering was the Oenach Carmain, a celebrated assembly of the Laigin, the people of south Leinster. An óenach, in early Irish society, was fundamentally an assembly of people, but the word carried older, darker meaning: these events had their origins in funeral rites, and so óenach became linked with major burial sites across Ireland, among them Tailtiu, Brú na Bóinne, and Emain Macha. The pairing of a prominent ring barrow with an assembly of this kind was not coincidental; the dead and the living shared the same ceremonial ground. Ó Murchadha, writing in 2002, concluded that Silliot Hill was the likely location for the Oenach Carmain, which was regarded as a particularly esteemed occasion among the Laigin. The barrow itself shows signs of having been interfered with over the centuries. When it was examined in 1955, the bank appeared partially remodelled, the fosse was noted as being effaced in places, and the remains of a ruined summer house sat on the bank and fosse at the north-western side, a Georgian or Victorian folly absorbed into a monument thousands of years its senior.