Cognomen Kalnius (Kalnius 
) , all over the world, is a rare last name. The cognomen Kalnius is habitual in Northern Europe, particularly Lithuania, where it is quite a rare surname.
| VARIANT | COUNTRY |
|---|---|
| Kalnius | Lithuania |
| alfonsas kalnius LT (b. 1907) |
|
|
| antanas kalnius LT (b. 1972) |
|