Allsvenskan is a Swedish professional league for men's association football clubs. It was founded in 1924, and is the top flight of the Swedish football league system, operating on a system of promotion and relegation with Superettan. Seasons run from late March or early April to the beginning of November, with the 16 clubs all meeting each other twice, resulting in a 30-match season, for a total of 240 matches league-wide.