Rathcroghan is one of the four major Royal Sites of Ireland and is known as a place of burial and ritual gatherings. The legendary leader and Warrior Queen of Connacht, Medb, is said to have had her palace here at Rathcroghan around the turn of the first century.

It is here that epic stories such as the Táin began as oral tradition. The Rathcroghan mound was the focal point for the entire region and the very visual experience from the summit makes this all the more apparent. Adjacent are the mounds of Rathnadarve (Ráth da dTarbh), Rathbeg (An Ráthbeag) and Rathmore (An Ráth Mór). The site today extends over 6.5 square kilometres and encompasses over 240 archaeological sites.

Contained within this are 60 protected national monuments, ranging from natural limestone caves, ancient burial mounds and ringforts, ritual sites, linear earthworks and medieval field systems. Oweynagat (Uaimh na ngat – Cave of the Cats) is also set within the complex. The otherworldly Battle Goddess, The Mórrigan, is said to dwell within this cave; making the cave one of three on the Island allowing movement between this tangible, real world and The Otherworld. This association was later interpreted as The Gates of Hell or Hell’s Mouth.