Family name Tjarn (Tjarn 
, Tjern , Tjørn 
) , across the world, is an extremely rare cognomen. The family name Tjarn is characteristic of Norway, where it is a very rare surname, and the United States, where it is an extremely rare surname. Much less frequently, Tjarn is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Tjarn, Tjern | United States |
| Tjørn | Norway |