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