Oweninny Bog is situated on the headwaters of the Sruffaunnamuingabatia, a tributary of the Oweninny River, Bellacorick, Co. Mayo. This bog comprises rich-flush habitat that is uncommon outside North Mayo. There are rare plant species present on the property and it was designated as an NHA in 2001. The property has been designated as SAC (466) due to the occurrence of protected plant species: Saxifrage Hirculus, Homalothecium Nitens, and Meesia Triquetra.
Oweninny Bog contains a small minerotrophic fen developed on glacial till overlying calcareous sandstone. This particular Flush is of considerable interest, both due to the rich-flush habitat and the presence of rare plant species. Drains and extensive areas of mechanically-cut peat surround the entire site. The continued survival of this habitat, and the species which occur there, are threatened by a lack of grazing, as well as the drainage and peat-cutting activities occurring around the site.