Cognomen Ilii (Ilii 
, Илий 
) , in all the world, is a rare surname. The cognomen Ilii is habitual in Moldova, where it is quite a rare surname, Romania, where it is a rare surname, and Italy, where it is a very rare surname. Not in comparison with a country's population, it is commonest in Eastern Europe, particularly Moldova, Romania, and Russia. Likewise, Ilii is the forename as well as the last name.