Ostrów Wielkopolski is a city situated in west-central Poland within the Greater Poland Voivodeship. It serves as the administrative seat of Ostrów County and lies in the Kalisz Land, in the south-eastern part of historic Greater Poland. Geographically, it occupies a central position in a triangle formed by Poznań, Wrocław, and Łódź, lying approximately 100 kilometers from each of these major urban centers. The city is the fifth-largest in its voivodeship, following Poznań, Kalisz, Piła, and Konin.

The town received its first town rights in 1404, though economic stagnation led officials to drop this status in 1711 before it was reinstated with greater privileges later that year. It was annexed by Prussia during the Second Partition in 1793 and regained by Poles after the 1806 uprising, only to be re-annexed in 1815. The city played a vital role in Polish resistance, notably during the 1918 Republic of Ostrów upheaval and World War II, when it served as a center for the Polish Underground State before liberation on January 23, 1945.

The city features a well-preserved center with significant architectural heritage. Key landmarks include the Town Hall at the Market Square, which houses the local museum, and the Neo-Romanesque St Stanislaus' Co-Cathedral built in 1906. Other notable sites are the Church of Our Lady the Queen of Poland, erected in 1788, and the former synagogue. The city also contains the Old Cemetery, the oldest active Catholic cemetery in Poland, and several parks including Park 3 Maja and Park Miejski.

Ostrów Wielkopolski holds deep cultural significance as a center of Polish education, press, and national liberation movements. It is home to I Liceum Ogólnokształcące, one of the most renowned high schools in Greater Poland, originally established in 1845. The city commemorates its history through the Day of the City on November 10, marking the 1918 uprising. Visitors are drawn to its historical monuments, including those honoring Primate Mieczysław Halka-Ledóchowski, and its role in the Solidarity movement during the anti-communist strikes of 1980.

The city has a population of 70,725 as of 2021. Its economy historically benefited from the cloth industry and later from rail transport, with railway connections to Poznań and Kluczbork opening in 1875. Today, it is accessible via the S11 expressway bypassing the east and National Road 36 connecting to Krotoszyn. The city has a station on the Poznań-Opole railway line, with travel times of at least one and a half hours from Wrocław and Poznań.