Cognomen 昌沼 (昌沼 
) , throughout the world, is a very rare family name. The last name 昌沼 is habitual in Eastern Asia, particularly China, where it is an extremely rare surname. More frequently, 昌沼 is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| 昌沼 | China |