Borgata was part of a major project in Atlantic City nicknamed "The Tunnel Project", started around 1999. When Steve Wynn planned the Le Jardin in Atlantic City, he wanted to connect a $330 million 2.5-mile (4.0 km) tunnel from the Atlantic City Expressway to the new resort, later named the Atlantic City-Brigantine Connector, which would funnel incoming traffic off the Atlantic City Expressway into the city's marina district. This caused major controversy, as it would cut through a residential neighborhood and competitor Donald Trump sued Wynn for it saying that it was a "driveway" to his casino. The Tunnel Project did go on, even after Le Jardin was cancelled, finally opening in 2001.
Borgata opened on July 2, 2003 at 11:45pm, as a joint venture between MGM Mirage and Boyd Gaming. The main tower is the third tallest building in Atlantic City and is visible from many miles away due to its facade of reflective gold glass. The firms Marnell Corrao Associates of Las Vegas and Philadelphia’s Bower Lewis and Thrower Architects (BLT) worked on the project.
In late 2005 and early 2006, Borgata underwent a $200 million casino and retail expansion and the new wing opened in June 2006. As part of the expansion, Borgata installed a poker room, the largest in Atlantic City. In June 2008, Borgata opened its second hotel, The Water Club.
In early 2010, it was reported that MGM Mirage might sell its ownership share in Borgata. On March 12, 2010, MGM Mirage announced it would sell its stake in Borgata and stop doing business as a gaming licensee in New Jersey. On March 17, 2010, MGM Mirage announced that the New Jersey Casino Control Commission (CCC) approved the settlement agreement between the Company and the New Jersey Division of Gaming Enforcement (DGE) under which the Company would sell its 50% ownership interest in the Borgata.