Cognomen Sierraa (Sierraa 
) , globally, is a very rare last name. The last name Sierraa is characteristic of Latin America and the Caribbean, particularly Colombia, where it is a very rare surname, Mexico, where it is an extremely rare surname, and Argentina. Measured by absolute frequency, it is the most numerous in Colombia, Mexico, and the United States. Very seldom, Sierraa is the forename as well as the last name.