In 1714, one of the nobles of Ostrów, Jan Jerzy Przebendowski [pl], intervened at the royal court, for the status to be reinstated.

[3] By the power of Grand Crown Marshal Franciszek Bieliński, the town received its status back with greater privileges.

[3] The establishment of a railroad hub in Ostrów was a vital turning point in its development, helping to lend the town prominent status on the local and national scene.

[3] The Primate of Poland Cardinal Mieczysław Halka-Ledóchowski was imprisoned in the local prison for two years by the Prussians, before they eventually expelled him from the country.

[5] In the interbellum, Ostrów was one of the fastest growing towns: the number of inhabitants doubled, showy houses were built, as well as new schools, stadiums and a swimming pool.

[6] During the German occupation of Poland, local Poles were subjected to mass arrests, imprisonment, deportations to concentration camps, expulsions, forced labour and massacres.

In late 1939 and early 1940, many Poles were arrested during the Intelligenzaktion, then imprisoned in Kalisz and murdered in large massacres in the Winiary forest.

[7] Among the victims were activists, school principals, former participants of the Polish Greater Poland uprising (1918–19) against Germany, and pre-war mayor Stanisław Musielak.

[12] A Nazi German labor camp, Staatspolizeistelle Litzmannstadt Arbeitserziehungslager Ostrowo,[13] operated within the town's limits, where 193 people died.

The Germans carried out first expulsions of Poles in October 1939, focusing on owners of bakeries, cafes, workshops and large apartments, which were then handed over to German colonists as part of the Lebensraum policy, while expelled Poles were held in a transit camp in nearby Nowe Skalmierzyce for several weeks, and then deported to the General Government (German-occupied central Poland).

In September 1945, the Polish resistance movement made an unsuccessful attempt to capture the local communist jail and liberate the prisoners.

[20] In July–August 1980, employees of local factories joined the nationwide anti-communist strikes,[21] which led to the foundation of the "Solidarity" organization.