The Dungummin Ogham Stone, also known as the Clonkeiffy standing stone, is an ancient monument found on a field near a crossroads on the R194 road, south of Ballyjamesduff, County Cavan, in Ireland.
The Ogham stone is sandstone, is about 1.6m tall, 0.48m wide and 0.36m in thickness, tapering in the cross section almost to a point. The inscription on the north-western side is a personal name, ᚑᚃᚑᚋᚐᚅᚔ "OVOMANI". The western side of the stone is damaged. It was dated by S. Ziegler . The south side carries two crosses; in the west and north a cross is engraved.