Iloilo High School was founded in 1902 when an institution called Iloilo Normal School was established in a two-story building (now Casa Plaza) in front and cross the street of the present Provincial Capitol. It was established to meet the need for Filipino teachers. The minimum requirement for admission was the completion of the elementary education in the old Spanish schools The first batch of teachers were selected from among the experienced American teachers who were so-called Thomasites. They were transported to the Philippines via M/V Thomas. Once a teacher-institution, this school had gradually been converted to a secondary school after the building was transferred to Luna St., La Paz, Iloilo City which is the present site of the current school. The lot was donated by Don Francisco Jalandoni y Habana, a soldier and philanthropist. The construction of the building was at the expenses of the Provincial Government of Iloilo at that time. The building looked like more of a glorified farmhouse in the midst of rice and sugarcane fields, but it served as the center of learning, at its excellent level, at those early times. From then on, the school has produced brilliant leaders not only provincially, but nationally and internationally as well. A number of alumni have served in the United Nations, the White House, and other posts of national and local scope. Among the number of national leaders who came from INHS was Carolina Griño-Aquino who was once a Justice of the Supreme Court, Senator Meriam Defensor-Santiago, Congressman Arthur Defensor, Sr., former Governor Conrado Norada. The present Governor Niel D. Tupas, Sr. who is on his 3rd term also came from this school. Lots of other educators, members of the press, government employees and officials, local leaders have been produced by this school.