Family name 兰根 (兰根 
, Langen 
, Langan 
) , worldwide, is a common surname. The family name 兰根 is characteristic of Ireland, where it is quite a common surname, Netherlands, and Germany, where it is quite a rare surname. In absolute terms, this name is the most popular in the United States, Germany, and Netherlands. Very seldom, 兰根 is the forename as well as the last name.