Cognomen Usau (Usau 
, Усау 
) , in the world, is a rare family name. The cognomen Usau is characteristic of Nigeria, where it is a very rare surname, Malaysia, and Russia. Measured by absolute frequency, this name is the most popular in Nigeria, Russia, and India. Likewise, Usau is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Usau | Canada, India, Mexico, Nigeria, Malaysia |
| Усау | Russia |