Cagayan is the northernmost mainland province of the Philippines, occupying most of the Cagayan Valley — a broad, flat basin drained by the Cagayan River, the longest river in the country. The valley is bounded by the Cordillera Central to the west and the Sierra Madre to the east, with the Babuyan Channel and South China Sea to the north. Its isolation and fertility shaped a distinct regional culture centered on the Ibanag people and their neighbors.
Valley of the Great River
The Cagayan River runs 505 kilometers from the Caraballo Mountains in Nueva Vizcaya to the Babuyan Channel at Aparri, draining the entire valley. For centuries it was the main highway of the region — boats and bamboo rafts moved goods and people up and down its brown current. The river still floods seasonally, depositing fertile silt across the valley's rice and corn fields.
Callao Cave in Peñablanca, Cagayan, yielded fossil remains of Homo luzonensis in 2019 — a previously unknown species of archaic human that lived in the Philippines at least 50,000 years ago, and possibly over 67,000 years ago.
Tuguegarao City is the regional center for the Cagayan Valley and has the northernmost commercial airport in Luzon. The province is known for extreme heat — temperatures in the valley can reach 42°C during summer — and for equally extreme rainfall during typhoon season, as storms track directly through the northern Philippines.
