Grudziądz is a city in northern Poland, with 92,552 inhabitants (2021). Located on the Vistula River, it lies within the Kuyavian-Pomeranian Voivodeship and is the fourth-largest city in its province. The Old Town of Grudziądz and 14th-century granaries were declared National Historic Monuments of Poland.

The Vistula is the longest river in Poland and the ninth-longest in Europe, at 1,047 kilometres in length. Its drainage basin, extending into three other countries apart from Poland, covers 193,960 km2 (74,890 sq mi), of which 168,868 km2 (65,200 sq mi) is in Poland.