Janův Důl was formerly part of the German Empire. In the German Empire, the place was called Johannesthal (Reichenberg-Johannesth.).
The place is now called Janův Důl (Liberec-Janův Důl) and belongs to Czech Republic.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Johannesthal | Austro-Hungary | Reichenberg | before the Treaty of Saint-Germain |
| Janův Důl | Czechoslovakia | Liberec (venkov) | after the Treaty of Saint-Germain |
| Johannesthal | Czechoslovakia | Liberec (venkov) | after the Treaty of Saint-Germain |
| Johannesthal (Reichenberg-Johannesth.) | German Empire | Reichenberg (St.Kr.) | 1938 |
| Janův Důl | Czechoslovakia | Liberec, Statutární město | 1945 |
| Janův Důl (Liberec-Janův Důl) | Czechoslovakia | Liberec, Statutární město | 1945 |
| Janův Důl (Liberec-Janův Důl) | Czechoslovakia | Liberec | 1992 |
| Janův Důl (Liberec-Janův Důl) | Czech Republic | Liberec | 1993 |