Dłużnia was formerly part of the German Empire. In the German Empire, the place was called Dolgensee, Fh.
The place is now called Dłużnia and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Dolgensee, Fh | German Empire | Landsberg (Warthe) | 1939 |
| Dłużnia | Under Polish administration | Gorzów Wielkopolski | 1945 |
| Dłużnia | Poland | Gorzów | 1992 |