The term Congress Poland is an unofficial name of the Kingdom of Poland, a political entity that was created out of the Duchy of Warsaw at the Congress of Vienna in 1815, when European powers reorganised Europe following the Napoleonic wars. It had an area of roughly 127 000 km² and a population of approximately 2,600,000 (in 1814).

Congress Poland largely emerged as a result of the efforts of Adam Czartoryski, the Russian foreign affairs minister and a Pole who aimed to resurrect the Polish state in alliance with Russia. Formally, Kingdom of Poland was one of the few contemporary constitutional monarchies in Europe, with the Tsar of Russia as Polish King. The main problem was that the tsars, who had absolute power in Russia, similarly wanted no restrictions on their rule in Poland, while the country was given one of the most liberal constitutions in 19th century Europe. Congress Poland had a parliament which could vote on laws and was responsible to the tsar. It had also its own army, Polish currency, budget, penal code and was separated from the rest of Russian lands by a customs boundary.

Congress Poland lasted for a mere 15 years. Initially Alexander I was crowned as the King of Poland and obeyed the constitution. However, with time the situation changed and he granted the Grand Duke Konstantin Pavlovich with almost dictatorial powers. His successor, Nicholas I denied to crown himself as a Polish monarch and instead continued to limit the liberties of Poland. In 1831, the Polish parliament deposed the Tsar as King of Poland in response to his repeated curtailment of its constitutional rights. The Tsar reacted by sending Russian troops into Poland and the so-called November Uprising broke out.

The end of Congress Poland came with the crushing of the uprising following an 11-month military campaign. The constitution was abolished and the political entity was directly incorporated into the Russian Empire under the unofficial name of "Vistula Country " (Russian Privislinskiy Kray).

In 1863 the January Uprising started. After the defeat of the uprising, the official language of Congress Poland was changed to Russian, the Polish language was banned both from the office and education, and the process of liquidating the autonomy was finished.

Congress Poland was abandoned by the Russian army in 1915 and the following year the occupying Central Powers created the puppet Kingdom of Poland out of most of its territory.

Throughout the 19th century the term Congress Poland continued to be used in relation to these territories, although the political entity they were connected with no longer existed. The term Kongresówka is currently used in the Polish language as a slightly derogatory term for all inhabitants of central Poland, who are considered by some inhabitants of former Galicia as rude, uneducated and barbarian.