Saint Kerrill aka Caireall mac Curnain was a Christian missionary in what is now east County Galway, alive in the mid-to-late 5th century.
Caireall mac Curnain was a member of the Soghain people of Ireland, specifically those located in the kingdom of that name in what is now east County Galway.
Legends told about Kerrill include his fight with an Oll-phéist (terrible serpent) which was devastating the area about Cloonkeen.
A miracle told of Kerrill stated that his intercessions with God allowed Cianóg ní Cicharáin to become pregnant after years of a childless marriage.
She bore two daughters, who were the respective ancestors of Brian Boru and the Ó Conchobair Kings of Connacht.
There is a 14th Century Roman Catholic Church named Cille Choirill in Glen Spean, north of Ben Nevis, in the Lochaber district of the Scottish Highlands.
Local tradition maintains that it is named for the same St Kerrill whom it is believed, evangelized in the area before returning to Clonkeenkerril in East Galway.