The 10th-century ruins of Colmcille's abbey lie on a hillside to the north of Lough Gartan and northwest of Lough Nacally, beside a 16th-century chapel and an O'Donnell clan burial ground. It's signposted 1km north of Glebe House along a country road. There's a car park just up from the main road.
One kilometre south of the ruins, near the southeastern (hikers and cyclists only) entrance to Glenveagh National Park, is the saint's birthplace, marked by a hefty Celtic cross erected in 1911. Beside it is an intriguing prehistoric cup-marked slab strewn with greening copper coins. It's popularly known as the Flagstone of Loneliness on which Colmcille supposedly slept.