Jerka was formerly part of the German Empire. In the German Empire, the place was called Jägern.
The place is now called Jerka and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Jerka | German Empire | Kosten | before the Versailles Treaty |
| Jerka | Poland | Kościan | after the Versailles Treaty |
| Jerka | German Empire | Kosten (Wartheland) | 1939 |
| Jägern | German Empire | Kosten (Wartheland) | 1939 |
| Jerka | Poland | Kościan | 1945 |
| Jerka | Poland | Leszno | 1992 |