Dunajek was formerly part of the German Empire. In the German Empire, the place was called Duneiken.
The place is now called Dunajek and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Duneyken | German Empire | Treuburg | 1938 |
| Duneiken | German Empire | Treuburg | 1939 |
| Dunajek | Under Polish administration | Olecko | 1945 |
| Dunajek | Poland | Suwałki | 1992 |