Poznan known also by other historical names) is a city on the Warta River in west-central Poland, in the Greater Poland region. It is best known for its renaissance Old Town and Ostrów Tumski Cathedral. Today, Poznan is an important cultural and business centre and one of Poland's most populous regions with many regional customs such as Saint John's Fair (Jarmark Swietojanski), traditional Saint Martin's croissants and a local dialect.

Poznan is the fifth-largest and one of the oldest cities in Poland. As of 2019, the city's population is 534,813, while the Poznan metropolitan area (Metropolia Poznan) comprising Poznan County and several other communities is inhabited by over 1 million people. It is the historical capital of the Greater Poland region and is currently the administrative capital of the province called Greater Poland Voivodeship.

Poznan is a center of trade, sports, education, technology and tourism. It is an important academic site, with about 130,000 students and Adam Mickiewicz University, the third largest Polish university. Poznan is also the seat of the oldest Polish diocese, now being one of the most populous archdioceses in the country. The city also hosts the Poznan International Fair - the biggest industrial fair in Poland and one of the largest fairs in Europe. The city's most renowned landmarks include Poznan Town Hall, the National Museum, Grand Theatre, Fara Church, Poznan Cathedral and the Imperial Castle.

Poznan is classified as a Gamma- global city by Globalization and World Cities Research Network. According to several rankings it is one of the most business-friendly cities in Poland. It also ranks highly in safety and healthcare quality. The city of Poznan has also, many times, won the prize awarded by "Superbrands" for a very high quality city brand. In 2012, the Poznan's Art and Business Center "Stary Browar" won a competition organised by National Geographic Traveler and was given the first prize as one of the seven "New Polish Wonders".

The official patron saints of Poznan are Saint Peter and Paul of Tarsus, the patrons of the cathedral. Martin of Tours - the patron of the main street Swiety Marcin is also regarded as one of the patron saints of the city.