Last name Janahan (Janahan 
) , all over the world, is a rare cognomen. The family name Janahan is habitual in Sri Lanka, where it is quite a rare surname, the United Kingdom, where it is a very rare surname, and Philippines. Likewise, Janahan is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Janahan | Australia, Canada, Philippines, United Kingdom, Sri Lanka |