Szlasy-Leszcze was formerly part of the German Empire. In the German Empire, the place was called Szlasy Leszcze.
The place is now called Szlasy-Leszcze and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Szlasy Leszcze | Russian Empire | Cehanov | 1914 |
| Szlasy-Leszcze | Poland | Ciechanów | 1919 |
| Szlasy Leszcze | German Empire | Zichenau | 1939 |
| Szlasy-Leszcze | Poland | Ciechanów | 1945 |
| Szlasy-Leszcze | Poland | Ciechanów | 1992 |