Panamá, officially known as the Republic of Panamá, is a country in Central America, on the border with South America. It was where Nathan Drake had spend many of his adventures.
It's revealed in Uncharted 4: A Thief's End that Nathan Drake, Sam Drake, and Rafe Adler went to Panama to collect the Saint Dismas cross in the Panamanian jail led by the prison's corrupted warden, Vargas. Though successful, Sam was wounded and ended up staying in the prison for years. Nate abandoned the expedition, and Rafe continued searching for decades.
It was off the coast of Panamá that for centuries, Sir Francis Drake was believed to have been buried at sea, but an expedition by Francis Drake's supposed descendant Nathan Drake, and reporter Elena Fisher in 2007, revealed that the coffin was empty, except for Drake's lost diary. This proved Nate's theory that Drake had faked his death to cover up his latest discovery.