I Liga is the top professional football league in Poland, featuring 18 teams that compete annually. Established in 1927, it is organized by the Polish Football Association and operates on a system of promotion and relegation with the II Liga, the second tier of Polish football. The league typically runs from August to May, with each team playing 37 matches in a round-robin format. The team with the most points at the end of the season is crowned the champion, while the bottom teams face relegation to the lower division.