Kamienczyk, which was also called Kamieniec Mazowiecki, is located 5 kilometers east of Wyszkow.

This former town has a long history: in 1377 - 1795, it was the seat of a separate castellany (later a county), which belonged to Land of Nur, part of Mazovia.

The castellany of Kamienczyk/Kamieniec was established in 1377 in Sochaczew, during a meeting of dukes of the Duchy of Mazovia.

In 1526, together with whole Mazovia, it was annexed by the Kingdom of Poland, and was one of main administrative centers of eastern part of Masovian Voivodeship.

The town was completely destroyed during the Swedish invasion of Poland (1655 - 1660), and never regained its prominence.