Family name Siengo (Siengo 
) , in the world, is a rare cognomen. The family name Siengo is characteristic of Sub-Saharan Africa, particularly Kenya, where it is a rare surname, Tanzania, and South Africa, where it is an extremely rare surname. Measured by absolute frequency, the name is most common in Kenya, Tanzania, and the United States. Very seldom, Siengo is the forename as well as the last name.