The Argentine Primera División is the top professional football league in Argentina. Established in 1891, it features 28 teams competing annually for the championship. The league operates on a system of promotion and relegation with the Primera Nacional, the second tier of Argentine football. Matches are typically held from February to December, with each team playing others twice, once at home and once away. The league is known for its passionate fan base and has produced many famous clubs, including Boca Juniors and River Plate, which are among the most successful and popular teams in the country.