Janin was formerly part of the German Empire. In the German Empire, the place was called Hahnsfelde.
The place is now called Janin and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Janin | German Empire | Berent | before the Versailles Treaty |
| Janin | Poland | Kościerzyna | after the Versailles Treaty |
| Hahnsfelde | German Empire | Berent (Westpr.) | 1939 |
| Janin | Poland | Starogard Gdański | 1945 |
| Janin | Poland | Gdańsk | 1992 |