Ríoch, early Irish Christian missionary and Saint, fl. 490.
Ríoch or Moríóg[1] operated in the extreme west of Conmhaícne Mara, in what is now County Galway.
Oilean Da Chruinne contains the remains of a simple, early Christian oratory on the island's south side, which Ríoch is said to have built.
To the immediate east of the church is a small cemetery containing several very ancient headstones, traditionally held to be the graves of forty strangers who accompanied Ríoch from overseas.
Their identity is obscure but they are invoked in the Litany of Óengus of Tallaght, dating from the 8th century.