Thika is an industrial town and a major commerce hub in Kiambu County, Kenya, lying on the A2 road 42 kilometres, Northeast of Nairobi, near the confluence of the Thika and Chania Rivers. Although Thika town is administratively in Kiambu County, the greater Thika area comprising such residential areas such as Bendor estate, Maporomoko, Thika Greens, Thika Golden Pearl, Bahati Ridge, Thika Sports Club, among others, are within Murang'a County. Thika has a population of 279,429 which is growing rapidly, as is the entire greater Nairobi area. Its elevation is approximately 1,631 metres.
Thika is home to the Chania Falls, Fourteen Falls on the Athi River and the Thika Falls. Ol Donyo Sabuk National Park lies to the southeast. The town has a railway station with limited passenger service as only cargo trains operate, although there are plans to extend the proposed light rail system to Thika.
The town was the headquarters of Thika West district following the split of the larger Thika district into five districts: Thika East and Thika West, Ruiru, Gatundu and Gatanga.