The exact location is still to be determined by South American organiser CONMEBOL, which decided on Tuesday to stage the second leg on December 8 or 9.
The decision has yet to be validated by the football body’s disciplinary committee and it may yet be played behind closed doors, too.
The game is the South American equivalent of the Champions League final in Europe.
“It will be played outside Argentina because the conditions do not exist for the game to be played in Argentina,” Conmebol President Alejandro Dominguez told a news conference, following a meeting with representatives of River and Boca.
Boca Juniors President Daniel Angelici, however, said he will appeal the decision at the Court of Arbitration for Sport “if needed”. He said he did not agree on the new dates.
Paraguay, Brazil, the United States and Italy have offered to hold the highly anticipated match between the two arch-rivals. The first leg finished 2-2.
The two-week delay gives time for Boca players to recover from injuries suffered when their bus was attacked on Saturday en route to the final at River Plate’s stadium.
River fans hurled rocks and wood at the bus, shattering windows.
At least six players were injured, including Boca captain Pablo Perez who was hurt in the eye. Others were affected by tear gas and pepper spray used by police to disperse the River fans.
The match was postponed in light of the violence.
Boca wanted River to be disqualified at a disciplinary hearing with the club presidents on Tuesday at Conmebol headquarters in Luque.
Dominguez, the Conmebol president, said: “The conditions to play in Argentina are not right.”
“Football is not about violence, it is decided with goals,” he said. “Football is not what we saw on the weekend. That is a disease that needs to be eradicated.”