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