Formed in 1920 as the Sussex County Football League, started with just one league with 12 teams. By the end of the 1929–30 season, six of the original twelve teams remained, having played in every campaign since the competition began. The league saw regular changes in members between 1921 and 1928 and saw 23 different clubs taking part. The league closed down during the Second World War and the league ran two competition sections in the 1945–46 season, an Eastern division with eight teams and a Western division with 9 teams. The winners of each competition played in a play-off for a champion. A normal single league practice resumed in 1946 with 14 clubs now playing.