Tarnau was formerly part of the German Empire. In the German Empire, the place was called Ristenau (Kr. Obernick).
The place is now called Tarnowo and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Tarnowo | German Empire | Obornik/Obernick | before the Versailles Treaty |
| Tarnowo | Poland | Oborniki | after the Versailles Treaty |
| Tarnau | German Empire | Obernick | 1939 |
| Ristenau (Kr. Obernick) | German Empire | Obernick | 1939 |
| Tarnowo | Poland | Oborniki | 1945 |
| Tarnowo | Poland | Piła | 1992 |