It is an official MLB Partner League[2][3] based in the Mid-Atlantic and Southeastern United States, and the headquarters are located at Penn Medicine Park in Lancaster, Pennsylvania.

Two former Atlantic League players are in the National Baseball Hall of Fame and Museum, Tim Raines and Rickey Henderson.

The Atlantic League has had many notable managers and coaches, including Wally Backman, Frank Viola, Tommy John, Sparky Lyle, and Bud Harrelson.

The creation of the league was the result of the New York Mets' objection to Frank Boulton's proposal to move the former Albany-Colonie Yankees because of its territorial rights to the region.

Boulton, a Long Island, New York native, decided to create a new league that would have a higher salary cap for its players and a longer season than most of the other independent baseball organizations.

[15] In the summer of 2013, then-ALPB President Frank Boulton announced that he would be resigning so that he could devote more time to operating the Long Island Ducks.

[24] Shortly before the conclusion of the 2017 season, the city of Bridgeport, Connecticut voted to not continue with professional baseball in the city and announced plans to convert The Ballpark at Harbor Yard into a music amphitheater; the Bridgeport Bluefish announced plans to relocate to High Point, North Carolina in 2019 when the construction of a new multipurpose facility in High Point is completed.

This marked the first time that MLB, which has enjoyed a U.S. Supreme Court-granted antitrust exemption since 1922, had made any formal agreement with or acknowledgment of an independent baseball league.

[28] Several teams (Somerset, York, and Lancaster) did not gain necessary approval from governmental and health officials to open their ballparks to the capacity level necessary for competition.

Meanwhile, the Long Island Ducks, High Point Rockers, and Southern Maryland Blue Crabs initially attempted to partner with teams from other leagues in order to play a 70-game season from mid-July through the end of September.

[36] On September 1, 2021, the league announced the addition of a new Hagerstown, Maryland franchise with the intent to begin play in 2023 pending ballpark construction.

[42] In September 2023 it was announced that Spire City Ghost Hounds would be on hiatus during the 2024 season due to the league now having an odd number of teams with the addition of the Hagerstown franchise.