The League of Ireland is the top professional football league in the Republic of Ireland. Established in 1921, it features clubs from across the country competing for the championship title. The league operates on a promotion and relegation system with the First Division, which is the second tier of Irish football. The league consists of two main divisions: the Premier Division and the First Division. Each season, teams play each other in a round-robin format, with points awarded for wins and draws. The league is known for its passionate fan base and has produced several players who have gone on to play internationally.