Cognomen Tirto (Tirto 
) , in the world, is quite a common last name. The last name Tirto is characteristic of South-eastern Asia, particularly Indonesia, where it is quite a rare surname, Singapore, where it is a rare surname, and Malaysia, where it is a very rare surname. Measured by absolute frequency, it most frequently occurs in Indonesia, Japan, and Malaysia. Also, Tirto is the forename as well as the last name.