Oweynagat

Oweynagat (Uaimh na gCat, 'Cave of the Cats') is a souterrain attached to a natural limestone cave within the Rathcroghan royal site in County Roscommon, Connacht. Described in the 12th-century Book of Leinster as 'dorus ifrinn na hÉrenn' — Ireland's Gateway to Hell — it is the mythological lair of the Mórrígan and the site from which monstrous creatures issued each year at Samhain: a three-headed monster, red copper birds whose breath withered crops, and pigs that decayed whatever they touched. Medieval texts (Dindshenchas, Adventures of Nera) place the origin of the Cattle Raid of Cooley here. The cave is distinct from the Rathcroghan mound itself and has its own extensive textual tradition.