Between 1857 and 1899 there has been eight Leagues that is tracking. The table below lists those Leagues and sorts them according to Age, then First Year of play.

Each link goes to a League Page where you can find more information and individual season standings.

LeagueClassificationFirst YearAge
National LeagueMajor League1876 to now147 years old
American League (plus Western League  predecessor)Major League (plus Elite League predecessor)1894 to now (WL+AL)

1901 to now (AL)
129 years old

122 years old
National Association of Base Ball PlayersProto-League1857 to 187014 years old
American AssociationRival League1882 to 189110 years old
National Association of Professional Base Ball PlayersElite League1870 to 18755 years old
League AllianceRival League18821 year old
Union AssociationRival League18841 year old
Players LeagueRival League18901 year old
Table of Baseball Leagues (last updated Sep 2023) will be expanding this table as more standings are added.