Cognomen Singhagajen (Singhagajen 
) , across the world, is a very rare surname. The family name Singhagajen is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Singhagajen | Thailand |
Pornnabhasorn, Wantanee, and Thanakrid