Cognomen Илл (Illus 
, Илл) , in all the world, is a very rare surname. The family name Илл is characteristic of Estonia, where it is quite a rare surname, Finland, where it is a very rare surname, and Malaysia, where it is an extremely rare surname. Measured by absolute frequency, the name is most common in Estonia, Finland, and the United States. Likewise, Илл is the forename as well as the last name.