Family name Kumaja (Kumaja 
) , globally, is a very rare last name. The family name Kumaja is characteristic of Finland, where it is a rare surname, Tanzania, where it is a very rare surname, and India, where it is an extremely rare surname. Much less frequently, Kumaja is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Kumaja | Finland, United States, Tanzania, India, Brazil |