Area: 14,174.4 sq. km.
Population: 1,182.4 thousand habitants (2015).
Capital: Son La City.
Districts (11): Quynh Nhai, Muong La, Thuan Chau, Phu Yen, Bac Yen, Mai Son, Song Ma, Yen Chau, Moc Chau, Sop Cop, Van Ho.
Ethnic groups: Dao, Thai, Viet (Kinh), H'Mong, Muong.