Cognomen Ersain (Ерсаин 
, Ерсайн , Ersain 
) , all over the world, is a very rare family name. The last name Ersain is characteristic of Kazakhstan, where it is a very rare surname, Mexico, and Kyrgyzstan. In absolute terms, it most frequently occurs in Mexico, Kazakhstan, and Colombia. Predominantly, Ersain is the forename as well as the last name.