Arnoštka was formerly part of the German Empire. In the German Empire, the place was called Ernstberg.
The place is now called NN and belongs to Czech Republic.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Ernstberg | Austro-Hungary | Prachatitz | before the Treaty of Saint-Germain |
| Arnoštka | Czechoslovakia | Prachatice | after the Treaty of Saint-Germain |
| Ernstberg | Czechoslovakia | Prachatice | after the Treaty of Saint-Germain |
| Ernstberg | German Empire | Prachatitz | 1938 |
| Arnoštka | Czechoslovakia | Vimperk | 1945 |
| Arnoštka | Czechoslovakia | Prachatice | 1992 |
| NN | Czech Republic | Prachatice | 1993 |