Around the world, O'Riain (O'Riain 
) is an extremely rare unknown gender first name. Predominantly, O'Riain is the last name as well as the forename.
| VARIANT | COUNTRY |
|---|---|
| O'Riain | Australia, United Kingdom, France, Canada, Ireland |
| manus justin o'riain (born 1966) (b. 1966) |
|