The Knocknakilla megalithic complex (Grid Ref: W297843) that lies between Macroom and Millstreet, in County Cork, Ireland. It is set in blanket peatland on the north-west upper slopes of Musherabeg mountain and is thought to be 3500 years old. The area is rich with archaeological artifacts, and nearby are two cashels, a ringfort, two fulacht fiadh, a possible souterrain and a circular enclosure. The complex is best known for its large phallic and now leaning portal stone. Given the stones' relation to both the rising and setting sun, it is thought that they were aligned with purpose and functionality in mind, likely as calendars to early farmers, probably related to harvest or fertility ceremonies.
The main complex is found on a level patch of bogland overlooking a deep valley and comprises a recumbent stone circle, a radial cairn and two pointy typed portal stones (one of which has fallen), aligned north-northeast to south-southwest. The stone circle is made up of five 1.3- to 1.5-metre-high stones, of which two (the axis and east sidestone) fell sometime in the last 50 years. Only the two northern portal stones and a stone at the west stand today. The stone row, made up of two stones both over 3.5 metres tall, seems to have been aligned on the stone circle, although the stone nearest the circle has fallen, and the remaining stone has a pronounced lean. Three meters away is a 10-stone, 3.5-metre-diameter, radial cairn which was first discovered by Coillte Teoranta in 1970. The upright standing stone is 3.7 metres tall, and it leans heavily to the north.
Near the main site, a Dolmen made up from a long flat capstone supported by three upright stones is a modern re-construction.
- The word Knocknakilla is derived from the Irish Cnoc na Cille, as 'The Hill of the Church'
- "Knocknakilla". The Megalithic Portal. Retrieved 2008-06-14.
- Cork County Council, Information plaque located near the site.
- "Knocknakilla Recumbent Stone Circle - Co. Cork". Megalithics.com. Retrieved 2008-06-14.
- Power, Denis. Archaeological inventory of County Cork, Volume 3: Mid Cork, 9467 ColorBooks, 1997. ISBN 0-7076-4933-1