Family name 洪冈 (洪冈 
) , in all the world, is a very rare last name. The cognomen 洪冈 is habitual in Eastern Asia, particularly China, where it is an extremely rare surname. More prevalently, 洪冈 is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| 洪冈 | China |