Fenagh (Irish: Fiodhnach or Fíonach, meaning 'Woody Place')[2][3] is a village in the south-east of County Leitrim in Ireland.

[5] Fenagh Abbey is one of the oldest monastic sites in Ireland, believed to date back to the earliest period of Celtic monasticism.

Magnus, son of Muirchertach Muimnech (from the Annals of Connacht), wrote in 1244: Fedlimid mac Cathail Chrobdeirg made an immense hosting eastwards into Brefne against O Raigillig, to avenge his fosterson and kinsman, Tadc O Conchobair.

And as he was not present, the common soldiers of the host burned the huts and tents which were inside the church, without permission of their leaders, and the coarb's foster-child, God's gift, was suffocated.

He was buried outside the doorway of the church of Fenagh, and thrice the capacity of the Bell of the Kings of silver and thirty horses were given as an offering with him.

At Fenagh, two church ruins stand on the site of an earlier monastery founded by St. Caillin in the 6th century.

The main ruins of the Gothic church have (among other features) an east window of unusual design and a relief-carved 17th-century penal cross.

A number of standing stones in the vicinity represent the petrified bodies of druids who tried to expel St. Caillin from Fenagh.