Osow was formerly part of the German Empire. In the German Empire, the place was called Ostau.
The place is now called Osów and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Osow | Russian Empire | Veljunˈ | 1914 |
| Osów | Poland | Wieluń | 1921 |
| Ostau | German Empire | Welungen | 1939 |
| Osowa | Poland | Wieruszów | 1945 |
| Osów | Poland | Kalisz | 1992 |