Last name Promtorn (Promtorn 
) , worldwide, is an extremely rare cognomen. The family name Promtorn is habitual in South-eastern Asia, particularly Thailand, where it is an extremely rare surname. Much more prevalently, Promtorn is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Promtorn | Thailand |
Parkart, and Siriwannangkun