The Co Tu ethnic group, also called Gao, Ha, Phuong, and Ca Tang live in Tay Giang, Dong Giang and Nam Giang districts in Quang Nam Province, A Luoi and Phu Loc districts in Thua Thien-Hue Province.
The Co Tu believes in and worships Giang (Genie). The houses are set out cotuin the form of an ellipse. In the middle of the village is the Rong (Communal House), a large and beautiful building used for the reception of guests, to hold meetings, rituals and cultural performances. Patriarchy prevails among the Co Tu as the children take the family name of their father. The right of inheritance is reserved only for sons. Marriage dowries are also a common practice.
Men wear loincloths and leave their upper torsos naked. Women wear skirts and short vests. In winter they wear a piece of cloth to keep them warm. Popular ornaments consist of necklaces, bracelets, and earrings.
The Co Tu practice a slash and burn cultivation, often dig holes to plant seeds, practice animal husbandry, weave cloth and baskets, gather, hunt, and fish. The exchange of products is carried out by bartering.