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