Compostela Valley officially became the 78^th province of the Philippines on March 8, 1998 by virtue of Republic Act No. 8470 signed into law by  President Fidel V. Ramos on January 30, 1998.

Congressman Lorenzo S. Sarmiento, Sr. filed in 1967 the bill that eventually became Republic Act. No.4867. The Act subdivided the massive Davao Province into Davao Oriental, Davao del Norte, and Davao del Sur. His next step was to create another province from Davao del Norte but he died before it materialized.

His son, Rogelio M. Sarmiento, who succeeded him as congressman of the then 1^st district of Davao del Norte, pursued the plan with the support of then governor of Davao del Norte, Hon. Prospero S. Amatong, the province’s other two legislators - Congressman Rodolfo P. del Rosario of the 3rd district, and Congressman Baltazar A. Sator of the 2^nd district.

The said officials expanded the coverage of the proposed new province to include the municipalities of Maco, Mabini, Pantukan, and Laak with Nabunturan as capital town because of its strategic location.

The name originally proposed for the new province was Davao del Norte but it was not carried because of technical and legal issues. The issues were resolved when the lawmakers and the House of Representatives Research Bureau agreed on the name Compostela Valley because of the land’s vast fertile plain.

The province of Compostela Valley is composed of eleven municipalities politically-grouped into two legislative districts: District I – Compostela, Maragusan, Monkayo, Montevista, and New Bataan; and District II – Laak, Mabini, Maco, Mawab, Nabunturan, and Pantukan.  The province has a total land area of 4,666.93 square kilometers and is classified as a First Class Province.

At least nine ethnic tribes - Mansaka, Mandaya, Manobo, Mangguangan, Dibabawon, Aeta, Kamayo, Davaweño, and Kalagan – originally inhabited  the province. Today, the major tribes are the Mansaka, Kalagan or Ka’gan, Mandaya, Mangguangan, and Dibabawon.

The demography of Mindanao as well as Compostela Valley shifted significantly at the turn of the 20^th century with the influx of migrants from Luzon and the Visayas in the pre-world war and post-world war years. The bigger wave of immigrants arrived during the time of President Ramon Magsaysay in the 1950’s and early 60’s.

The logging boom by big-time concessionaires attracted additional thousands of migrants that eventually changed the demographic landscape of the province. Most of the ethnic tribes withdrew to the highlands and others inter-married and assimilated the culture and religion of the waves of people from Luzon, the Visayas, and parts of Mindanao.

Today, Compostela Valley is a virtual melting pot of ethnic groups dominated by a mostly Cebuano-speaking population and descendants of past migrants.