Cognomen Thelan (Thelan 
) , in the world, is a rare family name. The last name Thelan is habitual in Australia, where it is a rare surname, New Zealand, where it is a very rare surname, and the United States. Not in comparison with a country's population, this name is the most popular in Australia, the United States, and the United Kingdom. Also, Thelan is the forename as well as the last name.