The Boston Reds were a 19th century baseball team located in Boston, Massachusetts that played in the Players League in 1890 and in the American Association in 1891. They played in the Congress Street Grounds in the 1890s. The team took its name from the successful Boston club of the National Association and National League known as the Red Stockings who had changed their name to the Beaneaters in 1883. The club lasted only two seasons, but in those two seasons they were league champions.
In 1890 the Reds won the Players League Pennant when they finished first ahead of the New York Giants, and then won the American Association Pennant when they finished first ahead of the St. Louis Browns (now the Cardinals). The Boston Reds are one of two major league teams to win back-to-back pennants spanning two different leagues. The Brooklyn Dodgers did it also, winning the AA pennant in 1889 and the NL pennant in 1890.
At the conclusion of the 1891 season, the National League pressed for the consolidation of the American Association with the National League. Part of the posturing included the National League directing its champion Boston Beaneaters not to play the Reds in a World Series. The leagues settled, adding four AA clubs to a combined circuit. As part of the settlement, the owners of the four clubs not joining the combined circuit, including the Reds, were paid $135,000 and their players dispersed to the surviving clubs.