Cô Tô is an archipelago and a special administrative zone located in the northeastern region of Vietnam. It serves as a subdivision within the Quảng Ninh province, with its district capital situated in the town of Cô Tô.
The district covers a total area of 47.3 km2. As of 2019, it had a population of 6,285 residents, making it the lowest-population subdivision in Quảng Ninh province.