The Isabela State University was established through the Presidential Decree (P.D.) 1434 by the then President Ferdinand Marcos on June 10, 1978 merging two state colleges – Isabela State College of Agriculture (ISCA) in Echague and Cagayan Valley Institute of Technology in Cabagan. The said decree also transferred the college level programs of Isabela School of Arts and Trades (ISAT) in Ilagan; San Mateo Vocational and Industrial School in San Mateo and Jones Rural School in Jones to the new State University.

The merger identified Echague campus as the main campus and administrative site, and mandated the University to establish an effective and efficient institution of higher learning that will provide better professional and technical training in agriculture, the arts, sciences, humanities, and technology and in the conduct of scientific researches and technological studies.

The Administration Building Construction Plaque