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