The Isabela State University was established on June 10, 1978 when President Ferdinand E. Marcos issued PD 1434, merging the Isabela College of Agriculture (ISCA) at Echague and The Cagayan Valley Institute of Technology (CVIT) at Cabagan, and absorbing the college courses of the Isabela School of Arts and Trades (ISAT) in Ilagan, Roxas Memorial Agricultural and Industrial School (RMAIS) in Roxas, San Mateo Vocational and Industrial School (SMVIS) in San Mateo, and Jones Rural School in Jones, Isabela. The merging identified Echague campus as the main campus and its administrative site.
Pursuant to CHED Memo Order No. 18, s. 1999, CHED Supervised Institutions (CSIs) were integrated to the University. The first to be integrated was the Cauayan Polytechnic College at Cauayan, Isabela in 2000. In 2002, three other CSIs were integrated to the system, namely the Roxas Memorial Agricultural and Industrial School (RMAIS) in Roxas, Isabela; the Delfin Albano Memorial Institute of Agriculture and Technology (DAMIAT) in San Mariano, Isabela; and the Angadanan Agro-Industrial College (AAIC) in Angadanan, Isabela. Lately, two other campuses were added into the system: the Palanan and Santiago campuses.
The library in Echague campus was formerly located at the ISU Old Site, San Fabian, Echague, Isabela, under the supervision of Mrs. Romula Romero, the librarian. In 1982, the library was transferred to its two-storey building (University Library). Four other librarians took charge of the University Library, respectively. They are Dr. Oliva A. Karganilla (1986-May 2000), Mrs. Ruby A. Lumaban (June 2000-May 2007), Mrs. Merelisa R. Concordia (June 2007-January 2009), Ms. Dolores A. Ricardo (February 2009 to March 2010) and Mrs. Ruby Lumaban (April 2010 to present).
The library of ISU Angadanan is located at the 2nd Floor of the Science Laboratory Building. It has its lone librarian, Mrs. Erlinda Babaran. After her retirement, she was replaced by Mrs. Myrna M. Dela Cruz (June 2011-present).
ISU Jones library was first managed by Mrs. Clarita S. Rustia, the librarian. When ISU Jones Transferred to its own site, the library was located in the administration building from 2001 to 2006 with Mrs. Aileen J. Lagmay as the librarian in-charge.
Through the initiative of the administration and the generosity of a government official who allocated funds from his Priority Development Assistance Fund (PDAF), a Cyber Library, as it is called in Jones, was immediately constructed and started to operate in October 2007.
On July 27, 2009 up to the present, Dr. Betsie M. Dela Cruz, serves as full-time librarian of the campus. The Cyber Library continuously booms in terms of book collection and is responding to the challenge of globalization in education.