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