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