Płock is a city in central Poland, on the Vistula river, in the Masovian Voivodeship. According to the data provided by GUS on 31 December 2021, there were 116,962 inhabitants in the city. Its full ceremonial name, according to the preamble to the City Statute, is Stołeczne Książęce Miasto Płock. It is used in ceremonial documents as well as for preserving an old tradition.

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.