Cat Ba is a beautiful and poetic island, beautiful, located at an average height of 70m above sea level (ranges from 0–331 m). On this island, there is Cat Ba town in the southeast (overlooking Lan Ha bay) and 6 communes: Gia Luan, Hien Hao, Phu Long, Tran Chau, Viet Hai and Xuan Dam. Residents are mostly Kinh.

Cat Ba archipelago is a complex of 366 islands including Cat Ba Island in the south of Ha Long Bay, off Hai Phong city and Quang Ninh province, about 30 km from Hai Phong city center, Ha Long city. about 25 km.

Administratively, the archipelago belongs to Cat Hai island district, Hai Phong city. It has been recognized by UNESCO as a world biosphere reserve. Infrastructure is also quite developed with a combination of many hotels, motels, resorts, pagodas ...