Sejčin was formerly part of the German Empire. In the German Empire, the place was called Sýčina.
The place is now called Sýčina and belongs to Czechoslovakia.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Sejčin | Austro-Hungary | Jungbunzlau | before the Treaty of Saint-Germain |
| Sejčín | Austro-Hungary | Jungbunzlau | before the Treaty of Saint-Germain |
| Sýčina | Czechoslovakia | Mladá Boleslav | after the Treaty of Saint-Germain |
| Sejtschin | German Empire | Jungbunzlau | 1939 |
| Sýčina | German Empire | Jungbunzlau | 1939 |
| Sýčina | Czechoslovakia | Mladá Boleslav | 1945 |
| Sýčina | Czechoslovakia | Střední Čechy | 1992 |