Cognomen 洪瀚 (洪瀚 
) , across the world, is a very rare family name. The surname 洪瀚 is characteristic of Eastern Asia, particularly China, where it is an extremely rare surname. More prevalently, 洪瀚 is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| 洪瀚 | China |