Kalisz is a city in central Poland, and the second-largest city in the Greater Poland Voivodeship, with 97,905 residents. It is the capital city of the …Kalisz is a city in central Poland, and the second-largest city in the Greater Poland Voivodeship, with 97,905 residents. It is the capital city of the Kalisz Region. Situated on the Prosna river in the southeastern part of Greater Poland, the city forms a conurbation with the nearby towns of Ostrów Wielkopolski and Nowe Skalmierzyce.