Burundi ( (listen), ), officially the Republic of Burundi (Kirundi: Repuburika yUburundi, [u.u..ndi]; Swahili: Jamuhuri ya Burundi; French: Rpublique du Burundi, [buundi] or [byyndi]), is a landlocked country in the Great Rift Valley where the African Great Lakes region and East Africa converge. It is bordered by Rwanda to the north, Tanzania to the east and southeast, and the Democratic Republic of the Congo to the west; Lake Tanganyika lies along its southwestern border. The capital cities are Gitega and Bujumbura, the latter of which is the country's largest city.The Twa, Hutu and Tutsi peoples have lived in Burundi for at least 500 years. For more than 200 of those years, Burundi was an independent kingdom, until the beginning of the 20th century, when Germany ruled the region. After the First World War and Germany's defeat, the League of Nations "mandated" the territory to Belgium. After the Second World War, this transformed into a United Nations Trust Territory. Both Germans and Belgians ruled Burundi and Rwanda as a European colony known as Ruanda-Urundi. Burundi and Rwanda had never been under common rule until the time of European invasion of Africa.Burundi gained independence in 1962 and initially had a monarchy, but a series of assassinations, coups and a general climate of regional instability culminated in the establishment of a republic and a one-party state in 1966. Bouts of ethnic cleansing and ultimately two civil wars and genocides during the 1970s and again in the 1990s resulted in hundreds of thousands of deaths, leaving the economy undeveloped and the population as one of the world's poorest. The year 2015 witnessed large-scale political strife as President Pierre Nkurunziza opted to run for a third term in office, a coup attempt failed and the country's parliamentary and presidential elections were broadly criticised by members of the international community.

The sovereign state of Burundi's political system is that of a presidential representative democratic republic based upon a multi-party state. The president of Burundi is the head of state and head of government. There are currently 21 registered parties in Burundi. On 13 March 1992, Tutsi coup leader Pierre Buyoya established a constitution, which provided for a multi-party political process and reflected multi-party competition. Six years later, on 6 June 1998, the constitution was changed, broadening the National Assembly's seats and making provisions for two vice-presidents. Because of the Arusha Accord, Burundi enacted a transitional government in 2000. In October 2016, Burundi informed the UN of its intention to withdraw from the International Criminal Court.Burundi remains primarily a rural society, with just 13.4% of the population living in urban areas in 2019. The population density of around 315 people per square kilometre (753 per sq mi) is the second highest in Sub-Saharan Africa. Roughly 85% of the population are of Hutu ethnic origin, 15% are Tutsi, and fewer than 1% are indigenous Twa. The official languages of Burundi are Kirundi, French, and English, Kirundi being recognised officially as the sole national language.One of the smallest countries in Africa, Burundi's land is used mostly for subsistence agriculture and grazing, which has led to deforestation, soil erosion and habitat loss. As of 2005, the country was almost completely deforested, with less than 6% of its land covered by trees and over half of that being commercial plantations.Burundi is the poorest country according to gross domestic product (nominal) per capita, with 272$ in 2022, and a least developed country facing poverty, corruption, instability, authoritarianism, illiteracy, and more.

Burundi is densely populated, and many young people emigrate in search of opportunities elsewhere. The World Happiness Report 2018 ranked the country as the world's least happy with a rank of 156. Burundi is a member of the African Union, Common Market for Eastern and Southern Africa, United Nations and the Non-Aligned Movement. Burundi has the lowest GDP per capita as of 2022.

Rwanda, officially the Republic of Rwanda, is a landlocked country in the Great Rift Valley, where the African Great Lakes region and East Africa converge. Located a few degrees south of the Equator, Rwanda is bordered by Uganda, Tanzania, Burundi, and the Democratic Republic of the Congo. It is highly elevated, giving it the soubriquet "land of a thousand hills", with its geography dominated by mountains in the west and savanna to the east, with numerous lakes throughout the country. The climate is temperate to subtropical, with two rainy seasons and two dry seasons each year. Rwanda has a population of over 12.6 million living on 26,338 km2 (10,169 sq mi) of land, and is the most densely populated mainland African country; among countries larger than 10,000 km2, it is the fifth most densely populated country in the world. One million people live in the capital and largest city Kigali.

The population is young and predominantly rural; Rwanda has one of the youngest populations in the world, with the average age being 19 years. Rwandans are drawn from just one cultural and linguistic group, the Banyarwanda. However, within this group there are three subgroups: the Hutu, Tutsi and Twa. The Twa are a forest-dwelling pygmy people and are often considered descendants of Rwanda's earliest inhabitants. Scholars disagree on the origins of and differences between the Hutu and Tutsi; some believe differences are derived from former social castes within a single people, while others believe the Hutu and Tutsi arrived in the country separately, and from different locations. Christianity is the largest religion in the country; the principal language is Kinyarwanda, spoken by most Rwandans, with English and French serving as additional official languages. The sovereign state of Rwanda has a presidential system of government. The president is Paul Kagame of the Rwandan Patriotic Front (RPF), who has served continuously since 2000. Today, Rwanda has low levels of corruption compared with neighbouring countries, although human rights organisations report suppression of opposition groups, intimidation and restrictions on freedom of speech. The country has been governed by a strict administrative hierarchy since precolonial times; there are five provinces delineated by borders drawn in 2006. Rwanda is one of only three countries in the world with a female majority in the national parliament, the two other countries being Bolivia and Cuba.

Hunter-gatherers settled the territory in the Stone and Iron Ages, followed later by Bantu peoples. The population coalesced first into clans and then into kingdoms. The Kingdom of Rwanda dominated from the mid-eighteenth century, with the Tutsi kings conquering others militarily, centralising power and later enacting anti-Hutu policies. Germany colonised Rwanda in 1884 as part of German East Africa, followed by Belgium, which invaded in 1916 during World War I. Both European nations ruled through the kings and perpetuated a pro-Tutsi policy. The Hutu population revolted in 1959. They massacred numerous Tutsi and ultimately established an independent, Hutu-dominated republic in 1962 led by President Grégoire Kayibanda. A 1973 military coup overthrew Kayibanda and brought Juvénal Habyarimana to power, who retained the pro-Hutu policy. The Tutsi-led Rwandan Patriotic Front launched a civil war in 1990. Habyarimana was assassinated in April 1994. Social tensions erupted in the Rwandan genocide that followed, in which Hutu extremists killed an estimated 500,000–1,000,000 Tutsi and Hutu in the span of one hundred days. The RPF ended the genocide with a military victory in July 1994.

Rwanda's developing economy suffered heavily in the wake of the 1994 genocide, but has since strengthened. The economy is based mostly on subsistence agriculture. Coffee and tea are the major cash crops for export. Tourism is a fast-growing sector and is now the country's leading foreign exchange earner. Rwanda is one of only two countries in which mountain gorillas can be visited safely, and visitors pay high prices for gorilla tracking permits. Music and dance are an integral part of Rwandan culture, particularly drums and the highly choreographed intore dance. Traditional arts and crafts are produced throughout the country, including imigongo, a unique cow dung art.

Rwanda has been governed as a unitary presidential system with a bicameral parliament ruled by the Rwandan Patriotic Front since 1994. The country is a member of the African Union, the United Nations, the Commonwealth of Nations, COMESA, OIF and the East African Community.