Roztoky u Semil was formerly part of the German Empire. In the German Empire, the place was called Rostoky.
The place is now called Roztoky u Semil and belongs to Czechoslovakia.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Rostok | Austro-Hungary | Semil | before the Treaty of Saint-Germain |
| Roztoky | Austro-Hungary | Semil | before the Treaty of Saint-Germain |
| Roztoky | Czechoslovakia | Semily | after the Treaty of Saint-Germain |
| Rostok | German Empire | Semil | 1939 |
| Rostoky | German Empire | Semil | 1939 |
| Rostoky | Czechoslovakia | Semily | 1945 |
| Roztoky u Semil | Czechoslovakia | Východní Čechy | 1992 |