Cave in Glenballythomas

On the S-facing slope of Rathcroghan plateau, inside earthwork (RO022-057028-). It was considered to be the entrance to the underworld, and the residence of Morrigan, a pagan goddess of war, as well as being the dwelling of magical pigs, cats and other animals and spirits who emerged at Samhain or Halloween, the feast of the dead. (Gormley 1989b, 12-14) A stone-built and lintelled passage (dims 10.5m NNW-SSE; 0.75-1.4m; H 1-1.8m) of a Man-made underground passage (RO022-057029-) is partly rock-cut and descends from the blocked entrance at SE to a natural cave (dims 37m NNW-SSE; Wth of base c. 0.7-2.5m; max. H c. 7m). A second passage which joins the main passage close to the blocked entrance is now destroyed in its central part but allows access to the main passage through a short section (Wth 1.35m; H 0.9m) aligned ENE-WSW (L 2m), which serves as the present entrance to the whole structure. The original end of this passage is preserved as an inaccessible undifferentiated passage end (dims c. 1.5m x 1.5m) in the field bank c. 3m W of the present entrance to Oweynagat, although this has been interpreted as a separate Man-made underground passage (Waddell et al. 2009, 81-3). There is an ogham stone (RO022-057030-) at the junction of the two passages, and another (RO022-057084-) is at the SE end of the main passage. (Herity 1983, 132; 1987a, 138, Glenballythomas 17; Waddell 1983, 33, No. 21; Waddell 1988, 13-4; Condit and Moore 2003) This is a National Monument in state ownership: No. 473 Compiled by: Michael Moore Date of upload: 24 August 2010

The cave is situated in a limestone outcrop typical of the Carboniferous formations in the region, likely formed through dissolution processes over millennia. It has long been associated with Irish mythology, particularly as the entrance to the underworld and the dwelling place of the goddess Morrigan.