Dadaj was formerly part of the German Empire. In the German Empire, the place was called Schönfließ.
The place is now called Dadaj and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Schönfließ | German Empire | Allenstein | 1939 |
| Dadaj | Under Polish administration | Olsztyn | 1945 |
| Dadaj | Poland | Olsztyn | 1992 |