Cognomen Reiha (Reiha 
) , in all the world, is a very rare family name. The family name Reiha is characteristic of Latvia, where it is quite a rare surname, New Zealand, where it is a rare surname, and Australia, where it is a very rare surname. Not in comparison with a country's population, it is commonest in Latvia, Australia, and the United States. Very seldom, Reiha is the forename as well as the last name.