Surname Clahan (Clahan 
) , around the world, is a very rare cognomen. The last name Clahan is habitual in the United States, where it is a very rare surname, Thailand, where it is an extremely rare surname, and Canada. In absolute terms, this name is the most popular in the United States, China, and Thailand. Very seldom, Clahan is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Clahan | Canada, United States, Thailand, China |