The numbers are modest and the geography is not. The archipelago totals 75.79 square kilometres of land spread across sixteen mountainous islands and islets, and at the end of 2023 it held 13,112 people — a population that would barely fill a single block of the city it now belongs to. Almost everyone lives on Côn Sơn, the largest island, in a crescent-shaped valley between the hills and the sea. Thánh Giá mountain rises 577 metres behind the town. There is no land route to anywhere, so the archipelago runs on two lifelines: an airport at the northern tip of Côn Sơn, rated for about 400,000 passengers a year, and the boats. A daily overnight ferry from Vũng Tàu is less a passenger service than the island's supply chain, hauling in most of what cannot be grown or caught. In winter the sea between here and the mainland decides whether it sails.

The name that stuck to these islands on European charts for three centuries came from Malay sailors, who called the place Pulau Kundur — wax gourd island. The French rendered it Poulo-Condore and made it official. Underneath the names is some genuinely interesting rock. Hòn Bảy Cạnh, Hòn Cau and Hòn Bông Lang are built of Cretaceous microgranite. The northern half of Côn Sơn is quartz diorite and granite-granodiorite dating from the late Mesozoic into the early Cenozoic, with a thin skin of Quaternary marine sediment laid over parts of it. The southern half, and all of Hòn Bà, is rhyolite and related intrusions of undetermined age, and the western slope carries outcrops of diorite and microgranite shot through with broad quartz bands. The practical consequence of all this is an archipelago that is steep almost everywhere, forested where it is steep, and generous with flat, buildable ground almost nowhere.

For generations the islanders have kept a festival for a woman known as Bà Phi Yến. In the telling, she was a consort of the Nguyễn lord Nguyễn Phúc Ánh during his exile in the 1780s, and she urged him not to buy foreign military help, warning that a victory bought that way would not be his. He suspected her of disloyalty and had her shut in a cave. Their small son, Prince Cải, cried out for his mother during the evacuation, and his father killed him. Phi Yến survived, grieved, and took her own life. An Sơn temple, traditionally dated to 1785 and rebuilt in 1958 and again in 1981, holds a rockery representing the cave; it covers about 4,200 square metres and was listed as provincial heritage in 2009. It is a story about a woman who lost a child and then everything else, and the island has never treated it as anything less.

In early 2022 the Ministry of Culture, Sports and Tourism entered the festival on the national list of intangible cultural heritage — the first such listing anywhere in Bà Rịa–Vũng Tàu. Descendants of the Nguyễn Phúc line petitioned that April to have it struck off, arguing that it defamed their ancestor. Historians who examined the record found no consort named Lê Thị Răm or Phi Yến in the dynastic genealogies at all; noted that the title thứ phi, imperial concubine, was an anachronism for a man who was not yet emperor; and pointed out that the Côn Lôn of the story is more plausibly Koh Rong, off Cambodia. Several concluded the whole tale grew around an older cult of the sea goddess Thủy Long and was later attached to a historical figure known to have passed through. On 20 June 2022 the authorities found a middle path: the listing stayed, but the festival's official name was shortened to drop the imperial title. The offerings at An Sơn have not changed.

Since a fast ferry opened from Sóc Trăng in 2016, the archipelago has absorbed a wave of domestic visitors who come because Côn Đảo is regarded as sacred — a place where tens of thousands died in the prison camps. Thirteen thousand residents now host a great many more than that each year, on an island with one filling station and a fragile water supply. The pressure is not only from tourists. In 2020 the United States Navy sent warships through the surrounding waters on freedom-of-navigation operations, challenging what it called Vietnam's excessive maritime claims around the group. The islands spent two centuries being valuable to outsiders because they were far from everything. That has not stopped being true; only the reasons have changed.