Dluszek was formerly part of the German Empire. In the German Empire, the place was called Hartigswalde.
The place is now called Dłużek and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Dluszek | German Empire | Neidenburg | 1932 |
| Hartigswalde | German Empire | Neidenburg | 1939 |
| Dłużek | Under Polish administration | Nidzica | 1945 |
| Dłużek | Poland | Olsztyn | 1992 |