Halong City (formerly Hon Gai) is the provincial capital of Quang Ninh Province and the main gateway to Halong Bay — the UNESCO World Heritage-listed seascape of karst limestone islands that is one of Vietnam's most famous landscapes. The city sits on the bay's northern shore and is divided into two distinct parts: the eastern industrial and administrative zone (Hon Gai), and the western tourism strip around Bai Chay, where most of the hotels, restaurants, and tour operators are concentrated.
Most visitors pass through Halong City only to catch a junk cruise into the bay. The bay itself is the attraction — thousands of islands rising vertically from the water, caves riddling the limestone, and emerald-green water between the rock faces. Overnight or multi-day cruises leaving from Halong City (or from the nearby Tuan Chau Marina) are the standard way to see it. Day trips are possible but rush the experience.
The city itself is large and sprawling, with a working industrial character in the east. The ferry to Cat Ba Island leaves from the Tuan Chau ferry terminal.