Trzynietz was formerly part of the German Empire. In the German Empire, the place was called Trzynietz.
The place is now called Třinec and belongs to Czech Republic.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Trzynietz | Austro-Hungary | Teschen/Cieszyn,Český Těšín | before the Treaty of Saint-Germain |
| Trzyniec | Austro-Hungary | Teschen/Cieszyn,Český Těšín | before the Treaty of Saint-Germain |
| Třinec | Austro-Hungary | Teschen/Cieszyn,Český Těšín | before the Treaty of Saint-Germain |
| Třinec | Czechoslovakia | Český Těšín | after the Treaty of Saint-Germain |
| Trzyniec | Czechoslovakia | Český Těšín | after the Treaty of Saint-Germain |
| Trzyniec | Poland | Cieszyn/Český Těšín | 1938 |
| Trzynietz | German Empire | Teschen | 1939 |
| Třinec | Czechoslovakia | Český Těšín | 1945 |
| Třinec | Czechoslovakia | Frýdek-Místek | 1992 |
| Třinec | Czech Republic | Frýdek-Místek | 1993 |