Trans-Nzoia County is a county in the former Rift Valley Province, Kenya, located between the Nzoia River and Mount Elgon with its centre at the town of Kitale which is the capital and largest town of the county, and 380 km North West of Nairobi. It covers an area of approximately 2,495.5 sq Km with temperatures ranging between 10°C and 37°C, while average rainfall is around 11,200mm per annum and a population of about 818,757 people. The county borders the Republic of Uganda to the North West, West Pokot to North, Elgeyo Marakwet to the East, Uasin Gishu and Kakamega to the South, and Bungoma counties to the West and South West. It has 2 Local Authorities (Nzoia County Council, Municipal Council of Kitale) Kitale Town is the administrative headquarters. The county constitutes five constituencies: Cherengany,Kwanza, Saboti, Endebes and Kiminini.
Historically, the area has been inhabited by the Kalenjin and Bukusu people. After independence many of the farms vacated by white settlers were bought by individuals from other ethnic groups in Kenya.
Agriculture is the leading economic activity as the county is considered the bread basket of Kenya due to its large scale maize farming. The county is considered to be one of the most food secure in Kenya. Other economic activities include Horticulture, Wheat Farming, Tea, Coffee, , Fishing and commerce with Kitale Town being the main commercial hub.
The county hosts tourist attractions such as the Mt. Elgon National Park part of which sits the Mount Elgon, Kenya’s Second highest mountain, Kitale Nature Conservancy, Saiwa Swamp National Park.