The Democratic Republic of the Congo holds 102 million people as of 2024, making it the fourth most populous country in Africa. The population distributes across over 200 ethnic groups, the largest being the Luba, Kongo, Mongo, and Mangbetu-Azande clusters. Kinshasa contains 17 million residents, ranking it the second-largest Francophone city globally after Paris. French functions as the official language of government and formal education, while Lingala, Swahili, Kikongo, and Tshiluba serve as national languages with regional dominance. Lingala operates as the primary language in Kinshasa and the northwestern provinces, Swahili in the eastern regions, Kikongo in the west along the Atlantic coast and lower Congo River, and Tshiluba in the south-central Kasai provinces. The Catholic Church claims approximately 50 percent of the population, Protestant denominations another 20 percent, Kimbanguism 10 percent, and Islam 10 percent, with traditional belief systems practiced alongside or integrated with these formal religions in most rural areas.
The Kongo Kingdom controlled territory from the Congo River mouth inland to the Kwango River between the 14th and 19th centuries. Portuguese explorer Diogo Cão reached the Congo River mouth in 1482, initiating diplomatic and trade relations with the Kongo Kingdom capital at Mbanza-Kongo. The transatlantic slave trade from the Congo coast moved an estimated 5 million people between 1500 and 1850. King Leopold II of Belgium established the Congo Free State as his personal property in 1885 following the Berlin Conference. Forced labor in rubber extraction killed an estimated 10 million Congolese between 1885 and 1908 according to demographic studies comparing population records. International outcry led Belgium to annex the territory as Belgian Congo in 1908, removing it from Leopold's personal control. Patrice Lumumba, Joseph Kasa-Vubu, and Moïse Tshombe negotiated independence terms in Brussels in January 1960. Belgium granted independence on June 30, 1960, with Kasa-Vubu as president and Lumumba as prime minister.
Katanga province declared secession 11 days after independence on July 11, 1960, backed by Belgian mining interests in the copper industry centered on Lubumbashi. United Nations peacekeeping forces arrived in July 1960, reaching 20,000 troops by 1961. Military chief Joseph-Désiré Mobutu staged his first coup in September 1960, reversing it in February 1961. Lumumba was arrested in December 1960, transferred to Katanga, and executed on January 17, 1961. Mobutu seized permanent control in a November 1965 coup and renamed the country Zaire in October 1971. He renamed himself Mobutu Sese Seko and imposed a policy of "authenticité" requiring citizens to adopt African names and abandon Christian names between 1972 and 1990. The government nationalized foreign-owned businesses in 1973, leading to economic collapse as inexperienced administrators took control of mining, agriculture, and manufacturing operations. Inflation reached 9,800 percent in 1994.
Laurent-Désiré Kabila launched a rebellion from eastern Congo in October 1996 with backing from Rwanda and Uganda, whose governments sought to eliminate Hutu militant groups operating from refugee camps inside Congo. The Alliance of Democratic Forces for the Liberation of Congo-Zaire captured Kisangani in March 1997 and entered Kinshasa on May 17, 1997. Mobutu fled to Morocco, where he died from prostate cancer on September 7, 1997. Kabila renamed the country the Democratic Republic of the Congo and broke with his Rwandan and Ugandan backers in July 1998, expelling their military advisors. Rwanda and Uganda invaded in August 1998, starting a conflict that drew in armies from Angola, Zimbabwe, Namibia, Chad, and Sudan. The Lusaka Ceasefire Agreement signed in July 1999 failed to stop fighting. A bodyguard shot Kabila on January 16, 2001; he died on January 18. His son Joseph Kabila assumed the presidency at age 29.
The Second Congo War officially ended with the Global and All-Inclusive Agreement signed in Sun City, South Africa, in December 2002. Casualty estimates from 1998 to 2008 range from 3.8 million to 5.4 million deaths, most from disease and starvation rather than direct combat, according to the International Rescue Committee surveys. Joseph Kabila won elections in 2006 with 58 percent of votes in the runoff and in 2011 with 49 percent amid fraud allegations. Constitutional limits prevented him from running in 2016, but he delayed elections until December 2018. Félix Tshisekedi won with 38 percent, though Catholic Church observers reported discrepancies with their independent vote count. The transfer represented the first peaceful transition between elected leaders in Congo's history.