Port Chibaralta Island

Port Gibraltar Island is an island that was once the territory of the Whitebeard Pirates. It appeared in One Piece novel A.

Port Gibraltar Island was formerly ruled over by its boss Oliver. However, due to Oliver's involvement in the slave trade, which was forbidden by Whitebeard, he was deposed by the Whitebeard Pirates.

Past
Sometime in the past, Whitebeard claimed Port Gibraltar Island as his territory.

One Piece novel A
Portgas D. Ace was sent to lead an investigation on Port Gibraltar Island. There, he discovered that the island's boss Oliver was participating in the slave trade, and he forced Oliver to surrender and be arrested.

When Whitebeard was killed during the Battle of Marineford and the Whitebeard Pirates were defeated in the Payback War, Port Gibraltar Island lost the crew's protection and it is unknown what became of it.

Trivia

 * Port Gibraltar Island is likely named after the real-world location of the same name.