Surname Oonhwan (Oonhwan 
) , in the world, is a very rare cognomen. The last name Oonhwan is habitual in Thailand, where it is a very rare surname, and China, where it is an extremely rare surname. Much less frequently, Oonhwan is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Oonhwan | Thailand, China |