Cô Tô (listen) is a small rural district of Quảng Ninh province in the northeastern region of Vietnam. As of 2019, the district had a population of 6,285, which is the lowest-population district in Quảng Ninh. The district covers an area of 47.3 km². The district capital lies at Cô Tô.

Co To Island which has the ancient name Chang Son (Chang Mountain), has long been the residence of fishermen's boats in the Northeast but has not yet become a settlement because it was always harassed by Chinese pirates.

Under the Nguyen Dynasty, the population here became more crowded; most emigrated from China. Later, the island was occupied by French colonialists. In the middle of the 20th century, France withdrew. After that, the Chinese also returned home, the population on the island was only 10%, causing all production activities to decline.

On March 23, 1994, the government changed the name of Cam Pha district to Van Don district and split the Co To archipelago into two communes Thanh Lan and Co To to establish the Co To district.

In 2006, the population of the Co To Island district was 5,240 people with 1,178 households. Since 1994 until now, the state has had many supportive policies on electricity prices, petrol prices, construction and upgrading of infrastructure, and the daily passenger train Van Don - Co To, improving people's life in this area. This is constantly improving.

On October 16, 2013, Co To officially got electricity from the national grid when the project of bringing electricity to the island was completed, worth 1,106 billion VND.

After nearly 30 years of construction and development, by the end of 2022, the whole district has 1,957 households with 6,778 people from 13 ethnic groups and 14 provinces to live, build and develop the economy.

Co To has 71 large and small islands, of which the three largest islands are Co To Lon, Thanh Lan, and Tran. Co To Island and Thanh Lan Island are located close to each other and together with smaller neighboring islands form the Co To archipelago.

Co To sea area has a geographical location:

The East and the South border the waters of the Gulf of Tonkin

The West borders the sea area of the Van Don district

The North borders the sea area of Hai Ha district and Mong Cai City.

The district has an area of 53.68 km, the population in 2022 is 6778 people, and the population density reaches 126 people/km².

Co To has a mountainous terrain. The peak adjacent to Cap Chau on Thanh Lan Island is 210 m high, and the top of the big Co To Island meteorological station is 160 m high. The part between the islands is high, surrounded by low mountains and narrow fields, along the island are small sandy beaches and coves. The soil is mainly ferret on sandstone.

Forest land covers an area of 2,200 ha, Co To's agricultural land (771 ha) accounts for 20% of the natural land area, of which half are capable of cultivating rice and growing crops, nearly half are capable of grazing cattle, and other crops plant fruit trees.

Co To has few rivers and streams, dammed to form 11 small lakes. Abundant groundwater has good quality. The flora on the islands is quite rich and diverse. Diverse natural forest with many types of good wood.

The planted forest includes some species of trees such as casuarina, eucalyptus, and horsetail pine. Thanh Lan Island also has oranges, tangerines, and bananas that have become famous products in the province for many years. There are many rare medicinal herbs on all islands.

The fishing profession of shrimp, fish, squid ... in Co To island has been exhausted, so many types of seafood are prohibited from exploitation.

President Ho Chi Minh once visited Co To in 1961. In 1962, when he visited the Northeast, the Hai Ninh Provincial Administrative Committee asked for permission to erect a statue on Co To island, build a memorial house, set up beer in the places he visited, and got consent from Uncle Ho. This place is the pride of the island district; a historical milestone affirming the sacred sovereignty of the country, giving islanders pride, faith, and determination to stick with the sea.

There is a sedimentary rock system that has been eroded over thousands of years by seawater, creating a real wonder with beautiful scenery and valuable geomorphological research.

Unlike crowded and cramped beaches, this place still retains the inherent wild features, a clean, beautiful, pristine, and extremely peaceful blue beach.

The beach attracts the most tourists because it is located near the town center, with many shops, houses, and densely populated areas, so it is well known to many people. Near the beach, there is a monument of Uncle Ho. The coastline is nearly 7 km long with white sand, and smooth, clear water. On the beach side, there is a row of green pine trees, and a paved road running along the coast suitable for visitors to stroll in the afternoon.

The small island is located 7 km from Co To town, where there is a primeval forest containing many rare animals, in the sea containing many beautiful coral reefs.

Co To lighthouse is located in the eastern archipelago of Van Don island, Quang Ninh province. Located on a mountain about 5 km from the town, is the highest point of the island. This building was built in the late 19th century. The road from the foot of the mountain to the lighthouse is winding under the dense forest foliage.

As a place where ships on the sea can anchor to avoid storms, Au Port has many giant concrete pillars. With a convenient and cool location, this is a place to watch the beautiful sunset that is loved by many young people.

Currently, the district has 3 commune-level administrative units including Co To town and 2 communes Thanh Lan and Dong Tien. The whole district has 13 villages and zones, of which: 5 villages belong to Dong Tien commune, 4 villages belong to Thanh Lan commune and 4 areas belong to Co To town.

21°00′00″N 107°46′12″E / 21.000°N 107.77°E / 21.000; 107.77