Illzach was formerly part of the German Empire. In the German Empire, the place was called Illzach (Mülhausen-Illzach).
The place is now called Illzach and belongs to France.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Illzach | German Empire | Mülhausen | before the Versailles Treaty |
| Illzach | France | Haut-Rhin | after the Versailles Treaty |
| Illzach (Mülhausen-Illzach) | German Empire | Mülhausen (St.Kr.) | 1940 |
| Illzach | France | Haut-Rhin | 1945 |
| Illzach | France | Haut-Rhin | 1993 |