Last name 朗根 (Langen 
, Langan 
, 朗根 
) , globally, is a common cognomen. The surname 朗根 is characteristic of Ireland, where it is quite a common surname, Netherlands, and Germany, where it is quite a rare surname. In absolute terms, the name is most common in the United States, Germany, and Netherlands. Very seldom, 朗根 is the forename as well as the last name.