One of Ostrzeszów's honorary citizens is Krzysztof Wielicki, who climbed all of the world's mountains of over 8,000 metres (26,247 feet) in height.

In the 14th century, Polish King Casimir III the Great erected a castle, defensive town walls and the Gothic church of the Assumption of Mary.

[3] Ostrzeszów was a Polish royal town[3] and county seat[4] within the Sieradz Voivodeship in the Greater Poland Province.

Ostrzeszów prospered in the early modern era, multiple craft guilds were founded and trade flourished until the Swedes destroyed the castle and the town in 1656 during the Swedish invasion of Poland (Deluge).

In 1807 it was regained by Poles and included within the short-lived Duchy of Warsaw, in 1815 it was reannexed by Prussia, and from 1871 to 1918 it was part of Germany, however, in the early 20th century its population was still predominantly Polish.

[3] During the German invasion of Poland, which started World War II, the Einsatzgruppe III entered the town on September 6–7, 1939, to commit various crimes against Poles.

[9] During the subsequent German occupation it was annexed directly to Nazi Germany, and was administered within the newly formed province of Reichsgau Wartheland.

[11][12] Also Franciscans from Niepokalanów were held there, including Maximilian Kolbe, who was later killed in the Auschwitz concentration camp and is now considered a saint of the Catholic Church.

Its activities included espionage of German operations, sabotage actions, preparations for an uprising, printing and distribution of Polish underground press, which was also smuggled to the Stalag XXI-A, smuggling either radios or parts to build radios to British and Norwegian POWs, assisting POWs in escaping the camp, and providing aid to the most affected local families.

In July 1980, employees of the local mechanical equipment factory joined the nationwide anti-communist strikes,[22] which led to the foundation of the "Solidarity" organization.

The officially protected traditional foods originating from Ostrzeszów (as designated by the Ministry of Agriculture and Rural Development of Poland) are: