Gadomiec-Trojany was formerly part of the German Empire. In the German Empire, the place was called Gadomiec Trojany.
The place is now called Gadomiec-Trojany and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Gadomiec Trojany | Russian Empire | Prasnyš | 1914 |
| Gadomiec-Trojany | Poland | Przasnysz | 1919 |
| Gadomiec Trojany | German Empire | Praschnitz | 1939 |
| Gadomiec-Trojany | Poland | Przasnysz | 1945 |
| Gadomiec-Trojany | Poland | Ostrołęka | 1992 |