Kosin was formerly part of the German Empire. In the German Empire, the place was called Kosin.
The place is now called Kosin and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Kosin | Russian Empire | Lenčica | 1914 |
| Kosin | Poland | Łęczyca | 1921 |
| Kosin | German Empire | Lentschütz | 1939 |
| Kosin | Poland | Łęczyca | 1945 |
| Kosin | Poland | Płock | 1992 |