Cagayán is in the Cagayan Valley Region in the northeast of Luzon Island and its capital is the city of Tuguegarao. The Cagayan Valley is the largest region in the Philippines with regards to the land area. The Cagayan River, the country’s longest, runs through its center and flows out to Luzon Strait in the north, in the town of Aparri.

-https://www.discoverthephilippines.com/provinces-in-the-philippines/