Surname Sumlong (Sumlong 
) , in the entire world, is an extremely rare cognomen. The family name Sumlong is habitual in Southern Asia, particularly India, where it is an extremely rare surname. More prevalently, Sumlong is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Sumlong | India, Thailand |
Tangoth, Suebsing, and Thuayseechang