Sønderborg * was formerly part of the German Empire. In the German Empire, the place was called Langenvorwerk.
The place is now called Sønderborg * and belongs to Denmark.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Langenvorwerk | German Empire | Sonderburg | before the Versailles Treaty |
| Ladegaard | Denmark | Sønderborg | after the Versailles Treaty |
| Sønderborg * | Denmark | Sønderjylland | 1993 |