Mountain Province: History
=== Spanish colonial era ===
The area of the Cordillera mountains proved difficult to control by the Spaniards. During the long Spanish rule, not much was done to bring the province under control. From 1566 to 1665, they sent expeditions to conquer the land but the rugged terrain and hostile indigenous population at the time were major obstacles to complete subjugation. The first serious effort to subjugate them was made in 1785 when soldiers were sent from Cagayan to put down a revolt of the Kalingas. A famous Spanish explorer, Guillermo Galvez, conducted more than 40 forays to the mountainous region.
Formerly called La Montañosa by the Spanish colonizers due to its mountainous terrain, the area was subdivided into 6 comandancias politico-militar.
On August 19, 1908, during the American rule, the Philippine Commission enacted Act No. 1876, which organized the entire area of the Cordilleras into one large province, named Mountain Province.
The first governor was Samuel Kane, and the town of Bontoc was made the capital. It was originally composed of the sub-provinces of Amburayan, Apayao, Benguet, Lepanto-Bontoc, Ifugao and Kalinga.
Amburayan was later abolished in 1920 and its corresponding territories were transferred to the provinces of Ilocos Sur and La Union. Lepanto was also reduced in size and its towns were integrated into the sub-provinces of Bontoc and Benguet, and to the province of Ilocos Sur.
Effective on April 7, 1967, Republic Act No. 4695 abolished the old Mountain Province, converting its sub-provinces into 4 independent provinces: Benguet, Ifugao, Kalinga-Apayao and Mountain Province (corresponding to the former Bontoc sub-province). Bontoc became the capital of the new Mountain Province.
Mountain Province would have been significantly affected by the Chico River Dam Project during the Marcos administration, as the Marcos regime's project would have flooded the municipalities of Sabangan, Sagada, Sadanga, Bontoc, Bauko, and parts of Barlig. However, the indigenous peoples of Kalinga Province and Mountain Province resisted the project and when hostilities resulted in the murder of Macli-ing Dulag, the project became unpopular and was abandoned before Marcos was ousted by the 1986 People Power Revolution.
On June 15, 1987, the Cordillera Administrative Region was established upon the issuance of Executive Order 220 by then-President Corazon Aquino, and Mountain Province was made one of its provinces.
Through Presidential Proclamation 682, October 4, 2024 was declared a special non-working day to commemorate the Provincial Indigenous People’s Day.