The voivodeship comprised the western part of the former Duchy of Greater Poland with its historic capital Poznań.

As the westernmost part of the Polish–Lithuanian Commonwealth it bordered on the Neumark region of the Imperial Margraviate of Brandenburg in the west, the Bohemian crown land of Silesia in the south and the Duchy of Pomerania in the north.

In the course of the First Partition of Poland in 1772, the voivodeship lost the northern area around Wałcz to the Prussian Netze District, the remains were annexed in 1793 and incorporated into the province of South Prussia.

As early as the times of Bolesław Chrobry, the Land of Poznań had its own voivodes, while the city of Poznań itself was main gord of the ancient Lechia (...) When, following the Testament of Bolesław III Krzywousty Poland was divided among his sons, for more than 150 years Greater Poland was a separate duchy.

In 1305 it was united with the Kingdom of Poland, by Wladyslaw Lokietek, who turned it into a voivodeship (...) In 1346, King Casimir the Great took control of the Wschowa Land, uniting it with Poznań Voivodeship.The voivodeship, split by the Warta river into two almost equal halves, made western part of Greater Poland.