[4][5] As baseball developed over 150 years ago in the Northeastern United States, it has been played and followed in the region longer than any other sport in the nation.

As of 2022, the Philadelphia Phillies, founded in 1883, are the oldest continuous same-name, same-city franchise in both Major League Baseball and all professional sports in the United States and Canada.

The lowest levels of professional baseball serve primarily as development systems for the sport's most inexperienced prospects, with the absolute bottom, the rookie leagues, occupying the major league squads' spring training complexes and making no effort to earn money on their own.

After cooperating but remaining legally separate entities since 1903, in 2000 the leagues merged into a single organization led by the Commissioner of Baseball.

The sport rose in popularity in the 1920s, and survived potential downturns during the Great Depression and World War II.

The city was also host to two other highly popular baseball teams in the National League, the Brooklyn Dodgers and the New York Giants, before their transfer to California beginning with the 1958 season.

The fierce National League rivalry between the former Brooklyn Dodgers and New York Giants was transferred to the West Coast when the teams became the Los Angeles Dodgers and the San Francisco Giants, and California has always been among the US states which have supplied the most players in the major leagues.

[13] The 1950s and 1960s were a time of expansion for the AL and NL, then new stadiums and artificial turf surfaces began to change the game in the 1970s and 1980s.

[2] Home runs dominated the game during the 1990s, and media reports began to discuss the use of anabolic steroids among Major League players in the mid-2000s.

Since 2021, the Minor League Baseball hierarchy is separated into the classes of AAA, AA, High-A, Low-A and Rookie.

This came as a result of the reorganization of Minor League Baseball, which added or contracted new teams, as well as the elimination of Short-Season A and Rookie-Advanced.

Today, 19 affiliated minor baseball leagues operate with 246 member clubs in large, medium, and small towns, as well as the suburbs of major cities, across the United States, Canada, Mexico, the Dominican Republic, and Venezuela.

The 2023 World Baseball Classic saw rivals Team USA and Samurai Japan play in the final.

This matchup was watched by up to 5.2 million Americans, more than the number of viewers at the MLB postseason NLDS and Wild Card Series.

Viewership peaked at 6.5 million as Shohei Ohtani struck out Mike Trout to secure Japan's 3rd World Baseball Classic Championship.

Players who enroll at junior colleges (i.e., two-year institutions) regain eligibility after one year at that level, Bryce Harper being a notable example.

The College World Series for Division I takes place in Omaha, Nebraska in June, following the regular season.

The eight winners then advance to the College World Series, a double elimination tournament (actually two separate four-team brackets) to determine the two national finalists.