Zajączki was formerly part of the German Empire. In the German Empire, the place was called Haasenberg.
The place is now called Zajączki and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Haasenberg | German Empire | Osterode i. Ostpr. | 1939 |
| Zajączki | Under Polish administration | Ostróda | 1945 |
| Zajączki | Poland | Olsztyn | 1992 |