Poznań is a city on the Warta river in west-central Poland, with a population of 556,022 in June 2009. It is among the oldest cities in Poland, and was one of the most important centres in the early Polish state, whose first rulers were buried at Poznań's cathedral. It is sometimes claimed to be the first capital of the kingdom of Poland.

Poznań is now Poland's fifth largest city. It is the historical capital of the Wielkopolska ("Greater Poland") region, and is currently the administrative capital of the province called Greater Poland Voivodeship.

Poznań is an important centre of trade, industry, and education, and hosts regular international trade fairs. It was the host city for the United Nations Climate Change Conference in December 2008, a key stage in the creation of a successor to the Kyoto Protocol. Poznań was a candidate city for European Capital of Culture in 2016.

For centuries before the Christianization of Poland, Poznań (consisting of a fortified stronghold between the Warta and Cybina rivers, on what is now Ostrów Tumski) was an important cultural and political centre of the Polan tribe. Mieszko I, the first historically recorded ruler of the Polans, and of the early Polish state which they dominated, built one of his main stable headquarters in Poznań. Mieszko's baptism of 966, seen as a defining moment in the establishment of the Polish state, may have taken place in Poznań.