[1] As of 1999, the district had a population of 457,105 and an area of 1,478 km².
[3] In 2013, Kirinyaga District effectively disappeared and Kirinyaga County was effected as per the constitution of Kenya.
[1] In 2007 new districts were created and Kirinyaga District was divided into four new districts: Kirinyaga Central with its administrative centre at Kerugoya; Kirinyaga East with its administrative centre at Kianyaga; Kirinyaga South with its administrative centre at Wanguru; and Kirinyaga West with its administrative centre at Baricho.
Following a High Court ruling in September 2009, that there are only 46 legal districts in Kenya.
[4] The County Council of Kirinyaga administered all of Kirinyaga District, except the area administered by the Municipal Council of Kerugoya /Kutus and the Town council of Sagana-Kagio.