The voivodeship was created by King Wladyslaw Lokietek, out of the territory of Duchy of Łęczyca, which had been established after the 1138 Testament of Bolesław III Krzywousty.

Zygmunt Gloger in his monumental book Historical Geography of the Lands of Old Poland gives a detailed description of Łęczyca Voivodeship: "Following the testament of Boleslaw Krzywousty, the Land of Łęczyca was a separate duchy, ruled by princes of the Piast dynasty (...) King Wladyslaw Lokietek reunited the duchy with Poland, making it a separate voivodeship.

Local residents were used to their own legal system, so King Władysław II Jagiełło decided to keep a separate official there.

In 1418, the szlachta of Łęczyca established its own rules, the 27 Articles of Constitutiones Terrae Lanciciensis generales (...) The voivodeship had the area of 80 square miles, stretching from Klodawa in the north, to the Pilica river in the south, where it bordered Sandomierz Voivodeship.

Local sejmiks took place at Łęczyca, where four deputies were elected to the Sejm, and additional two to the Greater Poland Tribunal at Piotrków Trybunalski.