Ostróda [ɔsˈtruda] (German: Osterode in Ostpreußenⓘ; Masurian: Ôstród; Old Prussian: Austrāti) is a town in northern Poland, in the historic region of Masuria.

In 1270 the Teutonic Order began constructing wooden earthworks to control the original settlement as well as defend the initial Polish and German settlers.

After the Battle of Grunwald in 1410, Claus von Doringe conquered the castle and delivered the town to the victorious Polish King Władysław II Jagiełło.

[1] The Polish king brought the body of Ulrich von Jungingen there before travelling to besiege Marienburg (Malbork); the regrouping Teutonic Knights recaptured Osterode a few months later.

In 1440, local nobility co-founded the anti-Teutonic Prussian Confederation, upon the request of which the town was incorporated to the Kingdom of Poland by King Casimir IV Jagiellon in 1454.

[2] During the subsequent Thirteen Years' War (1454–1466), the town was repeatedly captured by both the Poles and Prussian Confederation on one side and the Teutonic Knights on the other.

In the 19th century the town was part of territory dominated by the Polish language, and the Osterode district was inhabited mostly by Poles (71% in 1825, 65% in 1867).

[7] During World War I and the 1914 Battle of Tannenberg, General Paul von Hindenburg had his 8th Army headquarters at the Osterode schoolhouse.

[5] During World War II, some expelled Poles from Lubawa County were enslaved by the Germans as forced labour in the town's vicinity.

With the conquest by the Soviet Union and the Potsdam Agreement, the town became again part of Poland and most of the remaining German population was expelled.