Pieniężno [pʲɛˈɲɛ̃ʐnɔ] (former Polish: Melzak; German: Mehlsack [ˈmeːlˌzak] ⓘ)[2] is a town in northern Poland, located on the Wałsza River in Warmia, in the Warmian-Masurian Voivodeship.

During the Middle Ages, an Old Prussian fort called Malcekuke, loosely translated as "woods of the subterraneous" or "devil's ground", was located near the current site of Pieniężno.

The town's coat of arms depicts three bags of flour spaced in between a golden sword and a silver key, all on a blue background.

The website recalls a story that the inhabitants defied a Swedish siege in the 17th century by spilling their last sack of flour as a deception to convince them that they still had plenty of food left.

In 1466, the town was recaptured by Poles led by Jan Skalski, then unsuccessfully besieged by the Teutonic Knights,[5] and with the end of the war in 1466, Melzak decisively passed to Poland.

The town was renamed from Mehlsack to Pieniężno after Seweryn Pieniężny (1890-1940), an editor for the Polish-language newspaper Gazeta Olsztyńska in Olsztyn, imprisoned and murdered by the Germans during World War II.