Surname Силья (Silja 
, Силья 
) , all around the world, is a rare family name. The surname Силья is characteristic of Iceland, where it is quite a rare surname, Finland, where it is a rare surname, and Switzerland, where it is a very rare surname. Not in comparison with a country's population, it most frequently occurs in India, the United States, and Germany. Much more frequently, Силья is the forename as well as the last name.