The Portal Tomb of Drumanone (also known as Tinnacarra in Irish, Droim Inneona, or Ballynanultagh Dolmen) is situated in the western part of County Roscommon, northeast of a railway line, approximately three kilometers west of Boyle and north of the Boyle River in Ireland. Portal Tombs are megalithic structures found in the British Isles, characterized by two equally tall upright stones with a doorstone in between, forming the front of a chamber covered by a partially massive capstone.
The supporting stones of the chamber are nearly intact, although the approximately 4.5 meters by 3.8 meters capstone has collapsed due to the significant erosion of the stone mound. The two portal stones are over two meters high, and the 1.2-meter gap between them is sealed by the doorstone, which is of equal height to the portal stones. There are two additional stones on each side, with the western one shifted by the collapsed capstone. A small stone at the lower end of the structure may be the broken remains of the original end stone. The chamber’s original dimensions were likely about two meters. In 1954, the excavated chamber contained significant amounts of cremated bones and a small axe sourced from the abundant flint mine in Tievebulliagh in County Antrim.
Drumanone (also known as Knockmaa) has been associated with Cul Cessrach, the grave of the mythological figure Cessair.