Son La, the fifth largest province in the country, is located in the northwestern region of Vietnam. Son La province is a northwestern mountainous province. It has two large plateaus also named Son La and Moc Chau, and an immense area of crop fields. The rest consists of valleys, high hills and mountains, Son La province borders Laos to the south. The province is co-inhabited by various ethnic groups: the Xa, H'Mong, Dao, Muong, Kinh, Kh'Mu, Tay, Thai and so on. The Thai is the largest single ethnic group. Eighty percent of the province's natural area is covered with mountains.