Sielun Szlachecki was formerly part of the German Empire. In the German Empire, the place was called Sielun Szlachecki.
The place is now called Sieluń * and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Sielun * | Russian Empire | Makov | 1914 |
| Sieluń * | Poland | Maków | 1919 |
| Sielun Szlachecki | German Empire | Mackeim | 1939 |
| Sieluń-Majorat | Poland | Maków Mazowiecki | 1945 |
| Sieluń * | Poland | Ostrołęka | 1992 |