Poplacin was formerly part of the German Empire. In the German Empire, the place was called Popłacin.
The place is now called Popłacin and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Poplacin | Russian Empire | Gostyn | 1914 |
| Popłacin | Poland | Gostynin | 1921 |
| Popłacin | German Empire | Waldrode | 1939 |
| Popłacin | Poland | Gostynin | 1945 |
| Popłacin | Poland | Płock | 1992 |