Last name Янса (Jansa 
, Янса 
) , in the world, is quite a rare surname. The cognomen Янса is habitual in Slovenia, where it is quite a common surname, Czechia, and Finland, where it is quite a rare surname. In absolute terms, this name is the most popular in Czechia, Slovenia, and the United States. Also, Янса is the forename as well as the last name.