The Mexican League (, ) is a professional baseball league based in Mexico and the oldest running professional league in the country. The league has 18 teams organized in two divisions, North and South. Teams play 114 games each season. Five teams in each division advance to a four-round postseason tournament that culminates in the Serie del Rey, a best-of-seven championship series between the two division champions. The Mexican League has two affiliated minor leagues, the Liga Norte de México and Mexican Academy League. Though founded in 1925, the league joined the National Association of Professional Baseball Leagues (Minor League Baseball) in 1955, when it was designated a Double-A league. Some member teams entered player development contracts with teams in the National League at that time. Triple-A classification was granted in 1967. As part of the 2021 reorganization of the minors, the Mexican League was not included as a Triple-A league, though it continues to operate independently. League organization From 1925 to the 1960s, the league consisted of about six teams each season. The league expanded to eight teams in the 1960s. In 1970, after the circuit had grown to 10 teams, the league was split geographically for the first time. In 1979, the Mexican Central League was absorbed into the expanded Liga Mexicana de Beisbol (Mexican Baseball League). The newly expanded league featured a 20-team circuit with four divisions. However, after a series of team bankruptcies, the Mexican League was reduced to 14 teams in two divisions. Although there is a stable core of teams in the league, it is not unusual for clubs to relocate. Often, new incarnations of the teams come about through new owners. Teams also cease after unsatisfactory results or bankruptcy. Since its foundation in 1925, more than 90 teams have passed through the Mexican League, and the only organizations that have remained since their inception are the Sultanes de Monterrey (1939), Diablos Rojos del Mexico (1940), Tigres de Quintana Roo (1955), Saraperos de Saltillo (1970), and Piratas de Campeche (1980). The Acereros del Norte have played uninterrupted since 1982, the Olmecas de Tabasco since 1977, and the Leones de Yucatán since 1979. Teams Future teams Defunct teams The league has lost 12 teams since it was established in 1925. Champions Records Single season batting Single season pitching History Beginnings of Mexican baseball Some sources claim that baseball reached Mexican soil because of the US