Osowiec was formerly part of the German Empire. In the German Empire, the place was called Diestelberg.
The place is now called Osowiec and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Ossowiec | German Empire | Mogilno | before the Versailles Treaty |
| Osowiec | Poland | Mogilno | after the Versailles Treaty |
| Diestelberg | German Empire | Mogilno | 1939 |
| Osówiec | Poland | Mogilno | 1945 |
| Osowiec | Poland | Konin | 1992 |