Hammer was formerly part of the German Empire. In the German Empire, the place was called Hammer.
The place is now called Żeleźnica and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Hammer | German Empire | Flatow | before the Versailles Treaty |
| Hammer | German Empire | Flatow | after the Versailles Treaty |
| Hammer | German Empire | Flatow | 1939 |
| Żeleźnica | Under Polish administration | Złotów | 1945 |
| Żeleźnica | Poland | Piła | 1992 |