The Kingdom of Poland, informally known as Congress Poland or Russian Poland, was created in 1815 by the Congress of Vienna as a sovereign state of the Russian part of Poland connected by personal union with the Russian Empire under the Constitution of the Kingdom of Poland until 1832. Then, it was gradually politically integrated into Russia over the course of the 19th century, made an official part of the Russian Empire in 1867, and finally replaced during World War I by the Central Powers in 1915 with the nominal Regency Kingdom of Poland.
Though officially the Kingdom of Poland was a state with considerable political autonomy guaranteed by a liberal constitution, its rulers, the Russian Emperors, generally disregarded any restrictions on their power. Thus effectively it was little more than a puppet state of the Russian Empire. The autonomy was severely curtailed following uprisings in 1830-31 and 1863, as the country became governed by namiestniks, and later divided into guberniya (provinces). Thus from the start, Polish autonomy remained little more than fiction.
The territory of the Kingdom of Poland roughly corresponds to the Kalisz Region and the Lublin, Łódź, Masovian, Podlaskie and Świętokrzyskie Voivodeships of Poland, southwestern Lithuania and part of Grodno District of Belarus.