Liga TDP is a professional association football league in Mexico and the fourth tier of the Mexican football league system. Formerly known as Tercera División de México (1967–2017). The league is contested by 246 participating clubs, organized into two zones, divided into 18 groups by geographic location. The season consists of an annual tournament, and the champions are decided by a final knockout phase in each zone. The champions of Zona A and Zona B compete in the national final, known as Campeón de Campeones de la Liga TDP, the winners are crowned Liga TDP champions.