Cognomen Ниагу (Nyagu 
, Niagu 
, Ниагу 
) , across the world, is a rare family name. The cognomen Ниагу is habitual in Kenya, where it is quite a rare surname, Romania, and Bulgaria, where it is a rare surname. Measured by absolute frequency, this name is the most popular in Kenya, Romania, and Tanzania. Very seldom, Ниагу is the forename as well as the last name.