The Tboli, also known as T'boli, Tiboli, and Tagabili, are an old indigenous people living in South Cotabato, where the southwest coast range and the Cotabato Cordillera merge to form the Tiruray highlands, in an area circumscribed by a triangle formed by the town of Suralla, Polomolok, and Kiamba. Located within these boundaries are three major lakes which are important to the Tboli: Sebu, the largest and the most culturally significant; Siluton, the deepest; and Lahit, the smallest. Population estimates of the Tboli range from a low of 100,000 to a high of 227,000 (NCCP-PACT 1988). The 1980 census gives a figure of 7,783 Tboli-speaking households, comprising an estimated total of 38,915 Tboli. The National Museum census, as of November 1991 in South Cotabato, records 68, 282 Tbol