The Congo Free State, also known as the Independent State of the Congo, was a large state and absolute monarchy in Central Africa from 1885 to 1908. It was privately owned by King Leopold II, the constitutional monarch of the Kingdom of Belgium. In legal terms, the two separate nations were in a personal union. The Congo Free State was not a part of, nor did it belong to Belgium. Leopold was able to seize the region by convincing other European states at the Berlin Conference on Africa that he was involved in humanitarian and philanthropic work and would not tax trade. Via the International Association of the Congo, he was able to lay claim to most of the Congo Basin. On 29 May 1885, after the closure of the Berlin Conference, the king announced that he planned to name his possessions "the Congo Free State", an appellation which was not yet used at the Berlin Conference and which officially replaced "International Association of the Congo" on 1 August 1885. The Free State was privately controlled by Leopold from Brussels; he never visited it.

Leopold II was the second King of the Belgians from 1865 to 1909, and the founder and sole owner of the Congo Free State from 1885 to 1908.