Cognomen Ильг (Ilg 
, Ильг 
) , throughout the world, is quite a common family name. The surname Ильг is habitual in Western Europe, particularly Switzerland, where it is quite a rare surname, Germany, and Austria. Measured by absolute frequency, it most frequently occurs in Germany, the United States, and Switzerland. Much less frequently, Ильг is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Ilg | Brazil, Germany, United States, Switzerland, Austria |
| Ильг | Kyrgyzstan, Kazakhstan |