Cagayan State University was established in 1978, through the merger of eight existing schools in varying disciplines spread across the province at the north-east tip of Luzon Island.
Since the merger, it has added medicine, law, medical technology and engineering to its original set of faculties. Other schools include health sciences, entrepreneurship and accountancy, teacher education, tourism and hospitality management, criminal justice, forestry and aquatic science, agriculture, industrial technology, information and computer science, human kinetics, public administration, veterinary science, humanities and social sciences, and natural sciences and mathematics.
Most of the students study at the campus in Tuguegarao, divided between the Andrews campus inherited from the Cagayan College of Arts and Trades and the post-merger Carig site. The remainder study are on locations across the province, at Aparri, Gonzaga, Lal-lo, Sanchez Mira, Piat, Solana and Lasam.