Jarocin was formerly part of the German Empire. In the German Empire, the place was called NN.
The place is now called Jarocin and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Jarocin | Russian Empire | Plonsk | 1914 |
| Jarocin | Poland | Płońsk | 1919 |
| NN | German Empire | Plöhnen | 1939 |
| Jarocin | Poland | Płońsk | 1945 |
| Jarocin | Poland | Ciechanów | 1992 |