Nyandarua County is a County in the former Central Province of Kenya. Its capital and largest town is Ol Kalou.Formerly the capital was Nyahururu, which is now part of the Laikipia County. Nyandarua County has population of 596,268 and an area of 3,304 km2.The county is located on the northwestern part of the old Central Province, and contains the Aberdare Ranges.
The county was split into two in 2007: Nyandarua North District and Nyandarua South District. However, with the promulgation in 2010 of new constitution, these have been re-organised as sub counties of Nyandarua County . Daniel Waithaka was elected the first governor of the County 2013 General Election and Francis Kimemia seconds him in August 2017 elections.