Mrtnik was formerly part of the German Empire. In the German Empire, the place was called Mrtník.
The place is now called Mrtník and belongs to Czech Republic.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Mrtnik | Austro-Hungary | Hořowitz | before the Treaty of Saint-Germain |
| Mrtník | Austro-Hungary | Hořowitz | before the Treaty of Saint-Germain |
| Mrtník | Czechoslovakia | Hořovice | after the Treaty of Saint-Germain |
| Mertnik | German Empire | Horschowitz | 1939 |
| Mrtník | German Empire | Horschowitz | 1939 |
| Mrtník | Czechoslovakia | Hořovice | 1945 |
| Mrtník | Czechoslovakia | Beroun | 1992 |
| Mrtník | Czech Republic | Beroun | 1993 |