Mühlchen, Forsthaus was formerly part of the German Empire. In the German Empire, the place was called NN.
The place is now called Boruszyn * and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Mühlchen, Forsthaus | German Empire | Obornik/Obernick | before the Versailles Treaty |
| Boruszyn, Leśnictwo | Poland | Czarnków | after the Versailles Treaty |
| NN | German Empire | Scharnikau (Wartheland) | 1939 |
| Boruszyn, Osada leśnictwa | Poland | Czarnków | 1945 |
| Boruszyn * | Poland | Piła | 1992 |