Ray Church, Medieval church and national monument in County Donegal, Ireland

Ray Church is a ruined medieval church and National Monument 2.5 km northeast of Falcarragh, near the meeting of the Yellow River and the Ray River. Its rectangular walls keep wide round-arched windows. In the graveyard stands St Colm Cille's Cross, 5.56 m high and 2.26 m across, cut from slate and modelled on Saint John's Cross on Iona.

St Fionnán founded Ray Church in the 6th century, beside the Ray River, the old boundary between the Cenél Luighdech and Cenél Duach; four 7th-century abbots of Iona came from the Cenél Duach, and Ray was almost certainly their home church. In the 17th century Oliver Cromwell's soldiers destroyed the church and killed the congregation at Sunday Mass, the Massacre of Ray (Marfach Ráithe).

Local lore says the cross was made for Columba at Muckish for Tory Island, but Saint Fionnán recovered Columba's Gospel Book and received the cross in return. The cross is called St Colm Cille's Cross, and its model was Saint John's Cross on Iona.

The ruins sit roughly 2.5 kilometers northeast of Falcarragh village and are accessible by foot. The high cross is secured inside the church walls, making it easy to view up close without concern for damage.

The mass grave Lag na gCnámh, "Resting Place of the Bones", is said to hold the congregation killed at Sunday Mass when Cromwell's soldiers destroyed the church in the 17th century. The killing is remembered in Irish as Marfach Ráithe, the Massacre of Ray.