Family name Dellau (Dellau 
) , across the world, is a rare cognomen. The cognomen Dellau is habitual in the Democratic Republic of the Congo, where it is a rare surname, Belgium, and France, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Dellau | Democratic Republic of the Congo, Belgium, France |
| paul richard dellau DE (b. 1761) |
|
|
| johann pau joseph dellau (b. 1762) |
|