Cognomen Ilnyckyj (Ilnyckyj 
, Ільницький 
) , in the entire world, is quite a rare surname. The cognomen Ilnyckyj is characteristic of Ukraine, where it is quite a rare surname, Canada, where it is a very rare surname, and the United Kingdom, where it is an extremely rare surname. Measured by absolute frequency, this name is the most popular in Ukraine, the United States, and Canada.