The main residence and offices of the President of Rwanda are located in the city, as are the government ministries. The city is coterminous with the province of Kigali City, which was enlarged in January 2006, as part of local government reorganisation in the country. The city's urban area covers about 70% of the municipal boundaries.

Kigali was founded in 1907 by Dr. Richard Kandt under German colonial rule, but did not become the capital until Rwandan independence in 1962. The traditional capital was the seat of the mwami (king: Musinga, Rudahigwa and Kigeri IV) in Nyanza, while the colonial seat of power was in Butare, then known as Astrida. Butare was initially the leading contender to be the capital of the new independent nation, but Kigali was chosen because of its more central location. Since then the city has grown very quickly and is now the major political, economic and cultural centre of Rwanda.

Beginning on April 6, 1994, Kigali was the scene of the Rwandan Genocide – the slaughter of approximately one million Tutsi by Hutu militias (Interahamwe), and some members of the Rwandan army. There was fierce fighting between the army (mostly Hutu) and Tutsi-dominated Rwandese Patriotic Front. Although damaged, the city's structure has recovered.

The city is built in hilly country, sprawling across about four ridges and the valleys in between. The city centre is located on one of these ridges, with the main government area on another. The tops of the ridges have an average elevation of 1,600 metres (5,250 ft), while the valleys are around 1,300 m (4,270 ft). 

The bigger houses and office buildings tend to be on the tops of the ridges, while the poorer people live in the valleys. The city is ringed most of the way round by higher hills, with some suburban sprawl rising up these. The highest of these is Mt. Kigali, with an elevation of 1,850 m (6,075 ft) above sea level.

Considered a tropical savanna climate typically with a pronounced dry season. The Köppen Climate Classification subtype for this climate is Aw (Tropical Savanna Climate).

Kigali houses several memorials, museums, and centers dedicated to the Rwandan Genocide, including the Kigali Genocide Memorial Centre. Other museums include the National Museum of Rwanda and Kandt House Museum of Natural History.

Urugwiro is the official residence of the President of Rwanda. It constitutes an entire village within the Kacyiru distrct of Kigali.

The city has international class hotels, some played a role in history:

The Mille Collines in the Kiyovu area. This hotel became a refugee centre during the genocide, as famously depicted in the film Hotel Rwanda. It is also the setting for the famous novel Un dimanche à la piscine à Kigali, by Quebecer Gil Courtemanche, and its movie adaptation Un dimanche à Kigali.

The Kigali Serena Hotel, formerly known as the InterContinental Kigali. Formerly a Belgian-owned hotel known as Hotel Diplomates, the hotel was briefly portrayed in the second half of Hotel Rwanda. It was later bought by the InterContinental Hotels group and remodeled in 2003.

Kigali Convention Centre, currently under construction.