Nairobi's 2025 population is now estimated at 5,766,990. In 1950, the population of Nairobi was 137,456. Nairobi has grown by 225,820 in the last year, which represents a 4.08% annual change.These population estimates and projections come from the latest revision of the UN World Urbanization Prospects. These estimates represent the Urban agglomeration of Nairobi, which typically includes Nairobi's population in addition to adjacent suburban areas.
Nairobi is the capital of Kenya, which is located in Africa. In addition to being the capital, Nairobi is also the country’s largest city by population. The last official population was taken in 2009 and at that time was 3,138,369 in the city proper. That number has since grown to approximately 3.5 million. The metro area has over 6.5 million residents. This “Green City in the Sun” has a history dating back to 1899 and continues to grow as rural residents make their way to this big city for employment opportunities.
The city of Nairobi is growing consistently and currently sprawls over a surface area of 696 kilometers squared (269 square miles). This area size - in combination with the total number of residents - brings us the current population density which is now approximately 4,850 residents per square kilometer. (12,600 people living per square mile).
The primary languages of Nairobi are Swahili and English. The city is the location of one of the largest slums in the world, and approximately 22% of the city’s residents live in poverty.
Nairobi is a very ethnically diverse city, and Kenya’s major ethnic groups all reside here, including Luo, Luhyia and Kamba. The population is made up of 20% Kikuyu. There are also many Asians, Europeans, and Somalis that call this city home. A large number of expatriates live here because of the job opportunities, which has led to the city’s explosive growth.
Nairobi’s history goes back to 1899 when it became the site of the Uganda Railway’s headquarters. This railway line, meant to connect the East African interior with the rest of the world, had been named the “Lunatic Express” by skeptics doubting its economic worth. Prior to this, the city was uninhabited and was primarily swampland.
The original town was burned down during the 1900s after the plague hit its residents. The city was rebuilt, but in its earliest years, malaria was a growing issue, leading to attempts to move the town.
Under the rule of the British, the city grew. It was named as capital of the British protectorate and was named a municipality in 1919. The city continued to expand through the 1950s and 1960s. During this time, Nairobi would become a hot “big game hunting expedition” spot until independence came about. Following World War II, Kenya became independent and Nairobi was named as capital. In the early 1970s, the city continued its expansion, pouring $29 million into its airport.
In the 2000s, the city became even larger and mre modern, including the development of the Thika Superhighway. Today, the city is home to one of Adrica’s largest stock exchanges, is the site of international company headquarters including IBM, GE and Coca-Cola, and is known for Nairobi National Park, a popular destination for residents and tourists alike.
Nairobi is one of the fastest growing cities in Africa, quickly becoming the second largest city of the African Great Lakes. The city is growing at a rate of over 4% annually, primarily because of the high birth rates and immigrants that come to Nairobi searching for employment opportunities. It is estimated that the city will continue on its upward trajectory in terms of population, reaching 5 million in 2025.
| City | 2025 Pop. ↓ | Growth |
|---|---|---|
| Nairobi | 5,766,990 | 4.08% |
| Mombasa | 1,553,460 | 3.9% |
| Ruiru | 484,702 | 4.33% |
| Eldoret | 483,941 | 4.17% |
| Nakuru | 453,330 | 3.74% |
| Kisumu | 422,148 | 3.8% |
