Last name ธัญธนวิโรจน์ (ธัญธนวิโรจน์ 
) , in the entire world, is an extremely rare cognomen. The family name ธัญธนวิโรจน์ is characteristic of South-eastern Asia, particularly Thailand, where it is an extremely rare surname.
| VARIANT | COUNTRY |
|---|---|
| ธัญธนวิโรจน์ | Thailand |