A Look at the Oldest Active MLB Teams

All of these teams were founded before 1903, the year of the first official World Series. And, many of these teams were not known by their current moniker.

Cleveland’s first moniker, followed by the Napoleons, Naps, and Indians. Baltimore began play in 1901 as the Milwaukee Brewers (not to be confused with the current Brewers). The team lasted one season in Wisconsin before becoming the St. Louis Browns (1902-53).

Atlanta, meanwhile, started in Boston and became the Nationals in 1901. The Braves name was adopted in 1912 and temporarily ditched for the Bees from 1936-40.

Additionally, not all of these teams started in the current city. The Giants and Dodgers were both in New York for the first half of the 20th century. Most major baseball teams were situated near or on the East Coast of the United States at the time. The Athletics were based in Philadelphia before moving to Kansas City.

But aside from all that, one can see the core structure of the American and National Leagues. The first half of the 20th century in baseball was dominated by the likes of the Giants, Red Sox, and Tigers. The Yankees eventually became the behemoth of baseball but didn’t enter the American League until 1903.

Technically speaking, none of the above teams is as old compared to the Cincinnati Red Stockings, the oldest-known professional team to be in existence. The club was originally founded in 1866 and went fully professional in 1869.

Numbers from Baseball-Reference.