Last name Isaga (Isaga 
) , worldwide, is quite a common cognomen. The last name Isaga is habitual in Philippines, where it is quite a rare surname, India, where it is a rare surname, and Venezuela, where it is a very rare surname. Measured by absolute frequency, this name is the most popular in India, Philippines, and Nigeria. Very seldom, Isaga is the forename as well as the last name.