The longest river in Kenya is?

River tana is the longest river in Kenya with over one thousand one hundred km. It's known for electricity generation, irrigation and as a main source of water for Nairobi city.
The river starts from the Aberdares and Mt Kenya. It passes through Nyeri, and on the borders of Kirinyaga, Muranga, Machakos, Kitui, Embu, Tharaka Nithi, Meru, Tana River, Isiolo, Garissa and Lamu counties. It drains it's water in the Indian ocean at Ungwana bay. The river mouth features a delta that stretches about 30km upstream.
The river is known as Sagana or Thagana in the central highlands and Tana in the lowlands. The Name Tana comes from Tsana or Chana which means river in Pokomo language. The river, then gives its name to Tana River county where it covers a majority of its distance.
River Tana is fed by many tributaries; the main ones are Thika, chania, Gura, Thiba, Mathioya, Thuci, Mutonga and kathita. Some of the seasonal tributaries known as laga include Tula laga, Hirimani laga, Galole laga and Tiva laga.
The river and its tributaries form the tana river basin which is approx. 132,000 km2. This is about 22% of the country’s landmass. The basin support fishing, tourism and farming among other economic activities.
The river basin is host to several irrigation & settlement schemes . some of them include Sagana, Mwea Tabere, Bura, Tana and Tana delta irrigation schemes.
The river is host to the Seven Forks dams project. The name Seven forks comes from a natural feature between Gitaru and Kindaruma dams where the river splits into seven streams - referred to as, forks- before rejoining into one which is Contrary to the belief that there are seven dams.
The seven forks has a potential for 11 dams. However only 5 are complete. These Masinga, Kamburu, Gitaru, Kindaruma and Kiambere reservoirs. These dams contribute over 70% of hydro power in kenya, which is 38% of total electricity in the country. The incomplete ones are Karura, Low Grand falls, Mutonga, Usheni, Adamsons falls and Kora.
More so there are other dams on its major tributaries such as Thiba dam on river Thiba, mathioya dam on river mathioya and Ndakaini AKA Thika dam on river Thika. Ndakaini dam supplies over 80% of the water consumed in Nairobi.
The river supports the economy of surrounding areas by providing water for domestic, commercial and irrigation, Hydro electric power generation, fishing and tourism.
Some of the tourists activities include white water rafting and kayaking in the Sagana rapids, boat riding, Bungee jumping, site seeing and game tours in the surrounding parks.
Some of the parks within the river basin include Aberdare, Mt. Kenya, Meru, Kora and Arawale National Park and the Tana River Primate National Reserve.

[patrickmukora]

It's Thagana River in Nyeri where it meets Chania River and is still named Thagana River, until Masinga Dam where it changes to Tana River.