The Municipality of Diffun is a second class municipality in the province of Quirino, Philippines. According to the 2010 census, it had a population of 48,501 people. Commercial establishments proliferated along the provincial road due to its proximity to Santiago City as the main commercial hub of the region.
Diffun is politically subdivided into 33 barangays.
Quirino is a landlocked province in the Philippines located in the Cagayan Valley region in Luzon and named after Elpidio Quirino, the sixth President of the Philippines. Its capital is Cabarroguis.
The province borders Aurora to the southeast, Nueva Vizcaya to the west, and Isabela to the north. Quirino used to be part of the province of Nueva Vizcaya, until it was separated in 1966.
Long before its formal creation as an independent province, Quirino was the forest region of the province of Nueva Vizcaya, inhabited by tribal groups known as the Negritos. They roamed the hinterlands and built their huts at the heart of the jungle.
On June 18, 1966, Republic Act 4734 was enacted, constituting the municipalities of Diffun, Saguday, Aglipay, and Maddela (all of Nueva Vizcaya province) into a new sub-province to be known as "Quirino", named after the late Philippine president Elpidio Quirino.
On June 21, 1969, Republic Act 5554 was enacted, amending RA 4734 and creating the municipality of Cabarroguis (now the provincial capital town), which was taken from portions of Diffun, Saguday, and Aglipay.
Quirino may refer to: