Pietrzyk was formerly part of the German Empire. In the German Empire, the place was called Petersmühle.
The place is now called Pietrzyk and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Pietrzyk | Russian Empire | Rypin | 1914 |
| Pietrzyk | Poland | Rypin | after the Versailles Treaty |
| Petersmühle | German Empire | Rippin (Westpr.) | 1939 |
| Pietrzyk | Poland | Żuromin | 1945 |
| Pietrzyk | Poland | Ciechanów | 1992 |