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