Pelagja was formerly part of the German Empire. In the German Empire, the place was called Pelagja.
The place is now called Pelagia and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Pelagja | Russian Empire | Lask | 1914 |
| Pelagja | Poland | Łask | 1921 |
| Pelagja | German Empire | Lask | 1939 |
| Pelagia | Poland | Łask | 1945 |
| Pelagia | Poland | Sieradz | 1992 |