| 1876 | | The International Association for the Exploration of and Civilization of Africa is formed on the initiative of Leopold II King of the Belgians. The Association is headquartered in Brussels and forms committees in the principal countries of Europe. |
| | The Belgian Committee of the International Association establishes a station at Karema on Lake Tanganyika. |
| October | Henry Morton Stanley begins a 9 month exploration of 1600 miles on the Upper Congo between Nyangwe and Isangila. |
| 1878 | November 25 | Le Comité d'études du Haut Congo (subsequently renamed the International Association of the Congo) is established following a meeting between King Leopold II and Henry Morton Stanley. |
| 1880 | February | Henry Morton Stanley, agent for the International Association, establishes a station at Vivi. The first of 22 posts founded by Stanley over the course of the next four years. |
| 1884 | February | The British Foreign Secretary, Lord Granville, concludes a convention recognizing Portugal's claim to both banks at the mouth of the Congo. |
| April 22 | The United States becomes the first power to accord diplomatic recognition to the International Association of the Congo. |
| April 23 | Colonel Stauch, President of the International Association of the Congo, declares in a letter to the French Foreign Minister, that the Association will not cede its possessions to any power, "except in virtue of special conventions which may be concluded between France and the Association..." |
| August | Stanley returns to Europe. |
| November 8 | Germany recognizes the International Association of the Congo as a sovereign state. |
| November 15 | The Congress of Berlin convenes on the initiative of Chancellor von Bismarck to discuss the status of the Congo. |
| December | Great Britain, Italy, Austria-Hungary and the Netherlands recognize the International Association. |
| 1885 | January | France and Russia recognize the International Association. |
| February 5 | France accepts the International Association's claim to the Lower Congo and the Chiloango River as the boundary between French Congo and the Association's territory. |
| February | Sweden, Norway, Portugal, Denmark and Belgium recognize the International Association. |
| February 14 | The International Association concludes an agreement with Portugal ceding the south bank of the Congo below Noki to Portugal and retaining the north bank except for the enclave of Cabinda. |
| February 26 | The Congress of Berlin concludes with the signing of a General Act by the European powers and the International Association providing that, the trade of all nations shall enjoy complete freedom," in the Congo Basin. |
| April | The Belgian Chamber of Deputies authorizes King Leopold, "to be the chief of the state founded in Africa by the International Association of the Congo," but declares that, "the union between Belgium and the new State of the Congo shall be exclusively personal." |
| July 1 | The Independent State of the Congo is formally declared at Boma. |
| | A decree declares all vacant lands property of the Free State. |
| August 1 | King Leopold circulates a note to the major foreign powers defining the boundaries and declaring the neutrality of the Independent State of the Congo. |
| November 22 | The Congo Free State and France sign a protocol delimiting the boundaries of their possessions in the Manyanga region. |
| 1886 | | Captain Léon Roget organizes the Force Publique, a combination police and military force composed of native conscripts under European officers. |
| | Arab slave traders led by Chief Tippoo-Tib destroy the Free State government station at Stanley Falls. |
| | The Congo's rubber exports are valued at £6,000. |
| | The European population of the Congo numbers 254 of whom 46 are Belgians. |
| 1887 | April 22 | The Congo Free State informs the French Minister to Brussels that the preference granted to France in 1884 could be opposed by Belgium. |
| April 29 | France and the Congo Free State sign a protocol extending the boundary between the Free State and French Congo along the Congo and Ubangi to 4°North latitude. The Free State cedes all claims to the Niadi Kwilu Valley in which it had established 14 stations. |
| During the Year | Tippoo-Tib is appointed Governor of Stanley Falls representing King Leopold on the suggestion of Henry Morton Stanley. |
| 1889 | August | King Leopold bequeaths, "all our sovereign rights over the Independent State of Congo..." to Belgium. |
| 1890 | July 1 | Great Britain abandons plans to link its possessions from the “Cape to Cairo” and agrees to recognize German East Africa’s boundary with the Congo Free. |
| July | Belgium grants an interest free loan to the Congo Free State and in return is granted an option to annex the Congo at the end of the loan in 10½ years. |
| 1891 | May 25 | The Congo Free State and Portugal sign a treaty delimiting their possessions in the Luanda region. |
| September 21 | A secret decree is issued reserving a monopoly on the ivory and rubber trade in the vacant lands to the State. The natives are obliged to sell their produce to the State. |
| During the Year | An export duty imposed on ivory incites ill-will among Arab traders on the Upper Congo. |
| | The first concession companies, including the Anglo-Belgian India Rubber Company and the Société anveroise du commerce au Congo, are formed to exploit the resources of the Congo's vacant lands are organized under Belgian law. |
| 1892 | May | The murder of 11 Belgian traders on the Upper Lomani marks the beginning of the Arab War. |
| During the Year | A Belgian expedition under Commandant Dhanis captures Nyange and Kasongo breaking the power of the Arab traders in the Upper Congo. |
| 1894 | May 12 | The Congo Free State and Great Britain sign an agreement on the lease of territories in the Nile Valley and the boundaries of British Central Africa. |
| August 14 | The Congo Free State and France sign a boundary agreement delimiting their possessions on the Mbomu River and in the Congo and Nile basins. |
| 1895 | January 9 | The Belgian Government signs a treaty with King Leopold agreeing to take possession of the Congo Free State, its possessions, claims and obligations as of January 1, 1895. |
| February 5 | The Congo Free State and France sign an agreement delimiting their possessions in the Stanley Pool region. |
| During the Year | The Belgian Parliament refuses to ratify the treaty of annexation with King Leopold and instead approves further loans to the Congo Free State. |
| | Batetelas tribesmen in the Force Publique of the Lulua and Lomami districts stage a failed mutiny. |
| 1896 | | A secret decree creates the Domaine de la couronne, 112,000 square mile territory between the Kasai and the Ruki Rivers, considered the private property of King Leopold. |
| 1897 | | Batetelas tribesmen in the Force Publique murder several of their white officers and take control of a large portion of the Free State. The mutiny is not fully extinguish until three years later. |
| 1898 | | A 260 mile railway from Matidi at the mouth of the Congo to Stanley Pool (Leopoldville) is completed at cost of £2,720,000. |
| 1900 | | The Congo's rubber exports are valued at £1,158,000. |
| 1901 | January | The 1890 loan from Belgium to the Congo Free State expires. An annexation bill introduced in the Belgian Parliament is opposed by the Government and King Leopold. |
| August 7 | The annexation bill is withdrawn in favor of a Government sponsored measure extending the 1890 loan for an indefinite period. Belgium retains the right to annex the Congo but no date is specified. The terms of an organic act regulating the administration of any colonies Belgium might acquire in the future are published. |
| 1902 | | The existence of the Domaine de la courrone on the most valuable rubber producing lands in the Congo is officially acknowledged. |
| 1903 | May 20 | The British House of Commons declares, "That the government of the Congo Free State having, at its inception, guaranteed to the powers that its native subjects should be governed with humanity, and that no trading monopoly or privilege should be permitted within its dominions, this House requests His Majesty's Government to confer with the other powers, signatories to the Berlin General Act, by virtue of which the Congo Free State exists, in order that measures may be adopted to abate the evils prevalent in that state." |
| 1904 | February | The British Government releases a report by Roger Casement, its Consul at Boma, charging the Congo Free State with systematic maltreatment of the natives and contravention of the free trade clauses of the General Act of Berlin. |
| March | Edward Dene Morel and Roger Casement found the Congo Reform Association in London. |
| July | King Leopold appoints a three member commission to investigate the condition of the Congolese and if necessary recommend reforms. |
| 1905 | | Telegraphic communications between the Congo and Europe are established via cable from Libreville, Gabon. |
| November | King Leopold's investigatory commission confirms reports of grave abuses against the natives in the Congo. The commissioners accept the concessions and forced labor system as the only practical means of developing the country's resources but recommend reforms. The Commission calls for liberal interpretation of the land laws, enforcement of the law limiting forced labor to 40 hours per month, withdrawal of the concessionaire's right to employ compulsory labor, regulation of military expeditions and freedom of the courts from administrative control. |
| 1906 | May 9 | Great Britain and the Congo Free State sign an agreement for an extension of the railway above Stanley Falls to Lado at the head of navigation on the Nile. |
| June 3 | King Leopold intimates that he will modify his will to require that Belgium respect the arrangements he has made in regards to the governance of the Domaine de la courrone and the Domaine privè de la État as a condition of inheritance. |
| November 20 | British Foreign Secretary Edward Grey expresses displeasure with King Leopold's restrictions on Belgium's inheritance declaring, "Belgium should feel that her freedom of action is unfettered and unimpaired..." and goes on to says, "it will be impossible for us to continue to recognize indefinitely the present state of things without a very close examination of our treaty rights and the treaty obligations of the Congo State." |
| December 14 | The Belgian Chamber of Deputies responds to King Leopold's letter of June 3rd with a resolution declaring, "the Belgian legislature will regulate the regime of its colonial possessions in unrestricted liberty." The resolution is adopted by a vote of 128 to 1 with 30 Socialists abstentions. |
| November | The Congo Free State grants concessions to four new companies capitalized by British, French and American interests: |
| | Union minière du Haut Katanga is formed to develop the mineral wealth of Katanga. |
| | Chemin de fer du Bas Congo is formed to construct a railway from Leopoldville to Katanga. |
| | The American Congo Company is granted concession on the rubber trade in Kasai. |
| | Société internationale forestière et minière du Congo is formed to exploit the forests and mineral wealth of the state lands. |
| During the Year | A 79 mile railway is completed bypassing the Ponthierville rapids to connect the Congo at Stanley Falls with the Nyangwe - Lake Tanganyika railway via another 300 miles of navigable rivers. |
| 1907 | November 28 | The Belgian Government and the Congo Free State sign a treaty of cession. The treaty requires that the foundation established to administer the Domaine de la courrone be maintained and secured in all its privileges. The foundation's profits heretofore had been devoted to the maintenance of the royal family, royal palaces and estates in Belgium and projects of public utility. Belgium was accorded the right of redemption on terms which would have cost it £8,500,000 for ivory and rubber produced on the domain's alone. |
| | The Congo's rubber exports are valued at £1,758,000. |
| 1908 | January | The European population of the Congo Free State numbers 2,943 of whom 1,713 are Belgians. |
| February 26 | Foreign Secretary Edward Grey tells the British House of Commons that the Congo Free State has, "morally forfeited every right to international recognition." |
| | The British Foreign Office releases a report from W.G. Thesiger, its consul at Boma, detailing abuses in the application of the labor tax. Thesiger declares, "The system which gave rise to these abuses continues unchanged, and so long as it is unaltered the condition of the natives must remain one of veiled slavery." |
| March 8 | An act of the Belgian parliament repeals the clauses of the Congo cession treaty protecting the foundation administering the crown domains. Leopold II is permitted to retain a 155 square mile private estate in the Congo, a villa at Ostend and properties at Laeken and on the Riviera. The State will absorb the rest of the domaines de la courrone once it assumes sovereignty over the Congo and pay Leopold £2,000,000 over 15 years. |
| March 25 | The Belgian Parliament's Commission of XVII recommends that the provisions of the 1901 organic act governing administration of future colonies acquired by Belgium be changed to replace the absolute sovereignty of the king with parliamentary control. The British Foreign Secretary Edward Grey had declared any other solution unacceptable. |
| September 9 | The Belgian Senate enacts the final legislation clearing the way for annexation of the Congo. |
| November 14 | The Congo Free State ceases to exist. |
