Welchau was formerly part of the German Empire. In the German Empire, the place was called Welchau.
The place is now called Velichov (Žatec-Velichov) and belongs to Czech Republic.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Welchau | Austro-Hungary | Saaz | before the Treaty of Saint-Germain |
| Velichov | Austro-Hungary | Saaz | before the Treaty of Saint-Germain |
| Velichov | Czechoslovakia | Žatec | after the Treaty of Saint-Germain |
| Welchau | Czechoslovakia | Žatec | after the Treaty of Saint-Germain |
| Welchau | German Empire | Saaz | 1938 |
| Velichov | Czechoslovakia | Žatec | 1945 |
| Velichov (Žatec-Velichov) | Czechoslovakia | Louny | 1992 |
| Velichov (Žatec-Velichov) | Czech Republic | Louny | 1993 |