Ukkern was formerly part of the German Empire. In the German Empire, the place was called Ukkern.
The place is now called Okořín and belongs to Czech Republic.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Ukkern | Austro-Hungary | Komotau | before the Treaty of Saint-Germain |
| Okořín | Austro-Hungary | Komotau | before the Treaty of Saint-Germain |
| Okořín | Czechoslovakia | Chomutov | after the Treaty of Saint-Germain |
| Ukkern | Czechoslovakia | Chomutov | after the Treaty of Saint-Germain |
| Ukkern | German Empire | Komotau | 1938 |
| Okořín | Czechoslovakia | Chomutov | 1945 |
| Okořín | Czechoslovakia | Chomutov | 1992 |
| Okořín | Czech Republic | Chomutov | 1993 |