Surname Downan (Downan 
) , globally, is a very rare last name. The family name Downan is characteristic of Thailand, where it is a very rare surname, and the United States, where it is an extremely rare surname. Very seldom, Downan is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Downan | Thailand, United States |
Jasd, Poonyisa, and Pitchayanan