The term "Sureños" refers to a group of individuals, primarily in the United States, who identify with the Southern California gang culture. They are often associated with the Mexican Mafia and are known for their blue color symbolism. Sureños typically align themselves with various street gangs that operate in the southern regions of California and beyond. Sureños often use the number 13 to signify their allegiance, as it represents the letter "M," the 13th letter of the alphabet, which stands for Mexican Mafia. This group is involved in various criminal activities and has a complex hierarchy, with numerous affiliated gangs across the U.S. and Mexico.