Among the many mountains in That Son, the mountainous area of An Giang Province, Co To Mountain is the most beautiful. It is also one of the most frequently visited by pilgrims and tourists.

Co To Mountain is in Nui To Commune, Tri Ton District. It is about 50km from Chau Doc Town. The mountain is about 5,800m long, 3,700m wide and rises to 614m above sea level.

Apart from bearing the name Co To, the mountain is also called To Mountain or Phung Hoang Son. It looks like an overturned bowl, so it is called "To" which means "bowl." Connected with the mountain is Tuc Dup Hill. Seen from afar, the mountain and the hill resemble a phoenix, so people call the mountain Phung Hoang Son, which means "the mountain of a phoenix"

Co To Mountain is home for more than 30 households that mostly farm for a living. They grow fruit trees such as mangoes, jackfruits, durians, bananas, papayas, pineapples and avocadoes. Over the past several years, residents have also cultivated aquilegias for agar wood. Many people sell to visitors goods such as footwear, headwear, food, drinks and candles.

On the mountain, there are natural forests, places of interest and scenic spots. The places of interest are pagodas and temples. Visitors can spend the night at these pagodas if it is too late for them to leave the mountain or if they want to stay longer for more visits the next day. In addition, they can also stay overnight at simple guesthouses operated by residents.

One of the special scenic spots of Co To Mountain is San Tien (Fairy's yard). This site is about 200m above sea level. It is a rock yard with an area of more than 300m². It is fairly smooth and a bit steep. Near the far end of the yard below the top of the slope, there is a footprint in the rock. This right footprint is said to have been left by a fairy who stepped from Co To Mountain to Cam Mountain, about 8km away. His left footprint is on Cam Mountain.

Co To Mountain has visitors all year round but because of the fine weather it is more crowded from the time of the Lunar New Year holidays until the fifth lunar month.