The central part of the square is occupied by a group of buildings, with the Old Town Hall (Ratusz) being the most prominent among them. The sides of the square are lined with tall rows of former tenement houses (kamienice), many of which have been converted into restaurants, cafes, and pubs. These buildings often have outdoor seating areas on the square itself. The Old Market Square was originally laid out in 1253, with each side divided into 16 equal plots. Over the centuries, the architectural layout and style of the square underwent several changes, with the most significant ones being made by Giovanni Battista di Quadro in the mid-16th century. He reconstructed the Town Hall and several other buildings in the Renaissance style, following a fire that had caused severe damage to the buildings in 1536. The buildings in the square were heavily damaged during the Battle of Poznań in 1945, but were later reconstructed.
The central group of buildings in Poznan, Poland includes the Old Town Hall, standing in the northeast corner and facing east. In the same area is a row of 16th century merchants' houses, painted in a multicolored design and featuring an arcade with souvenir stalls. One of these houses, number 17, displays the coat of arms of the merchants' guild. Adjoining the merchants' houses is the former town chancellery, facing south. The old town weighing house, first built in 1532-1534, is located behind the Town Hall and faces north. After being rebuilt in 1950-1960 based on surviving prints, it is now used for weddings and other functions. On the opposite side of the square is the guardhouse, originally an 18th-century wooden building and rebuilt in Classical style in 1783-1787. It now houses a museum dedicated to the Greater Poland Uprising. The square also includes the Arsenał gallery, a postwar building standing on the site of a former market building, and the Wielkopolska Military Museum, standing on the site of a former cloth hall.
Notable houses around the edge of the square include: numbers 45, 46, and 47, which house a Museum of Musical Instruments; number 48, a reconstructed Gothic building; number 50, a reconstructed late-Gothic building; number 78, the Działyński Palace; and number 91, the Mielżyński Palace. The square also features a punishment post, a fountain depicting Proserpina, a statue of St. John Nepomucene, and fountains depicting the gods Apollo, Neptune, and Mars. Within the central group of buildings is a water fountain depicting a Bamber woman. The Pranger of Poznań is located near the northeast corner of the Poznan City Hall.