Brown confirmed he would be heading to Oakland on Twitter.
The 30-year-old will receive a new three-year contract worth $50.125 million, plus $4 million in incentives, according to NFL Network's Ian Rapoport. Brown gets $30.125 million of guaranteed money after his previous deal had none.
The trade marks the first major splash made by new Raiders general manager Mike Mayock. Brown will immediately fill a void as Oakland's No. 1 wideout after the club traded Amari Cooper to the Dallas Cowboys last season for a first-round pick in 2019.
Brown was reportedly on the verge of being traded to the Buffalo Bills earlier this week before he nixed a move to Western New York.
The Arizona Cardinals, New York Jets, Tennessee Titans, and Washington Redskins were among a list of teams who were believed to be interested in Brown's services at one point this offseason.
Brown has widely been considered the best pass-catcher in football over the past six years, averaging 114 receptions and 1,524 receiving yards per season over that span. He was made available via trade after a well-documented falling out in Pittsburgh, where his relationship with quarterback Ben Roethlisberger took a turn for the worse.