San Isidro was the capital of Nueva Ecija from 1852 to 1912. After the first cry against the Spanish colonial government was made in 1896, 2,000 revolutionary soldiers under General Mariano Llanera sieged San Isidro. On March 29, 1899, General Emilio Aguinaldo declared San Isidro as the capital of the Philippines after the revolutionary capital Malolos, Bulacan was captured by the Americans. However, this was short-lived. General Frederick Funston planned the capture of Aguinaldo to end the Philippine-American War, in San isidro. The Wright Institute, established in 1903 in San Isidro, was the first high school established outside Manila during the American period. The town was occupied by Japanese troops in 1942, during the second world war. The combined U.S. and Philippine Commonwealth ground forces liberated San Isidro and defeated the Japanese forces in 1945 during the end of the war.
Majority of populace is Roman Catholic. Other religious groups have churches and places of worship.
Economy
Primarily depends on rice & vegetable farming, poultry and piggery. As of 2017, based on Commission on Audit of the Philippines, San Isidro reached their income of P129,676,820.86; assets of P494,469,351.35; liabilities of P229,800,110.14 and allotments of P135,154,456.00.
Attractions
Carron Dreampark is an amusement & theme park in Barangay Santo Cristo, and was opened on November 17, 2017.
JF Sports Complex & Resort in Barangay Poblacion.
Education
Nueva Ecija University of Science and Technology, San Isidro Campus: started as a vocational course at the Wright Institute in San Isidro, Nueva Ecija where young Filipinos were trained in woodworking and basic telegraphy. This vocational course lasted until S.Y. 1927-1928 when the general secondary education course was transferred to Cabanatuan City. On June 9, 1929, the school was renamed Nueva Ecija Trade School in accordance with Vocational Education Act 3377 of 1929. The NETS was based in San Isidro, Nueva Ecija, offering vocational opportunities to the youth of the province. The first and only vocational course being offered then was woodworking. That course was an addition to the existing secondary curriculum inherited from the Wright Institute.
General de Jesus College: formerly known as General de Jesus Academy, is a private school located in the Poblacion, San Isidro, Nueva Ecija, the Philippines. It was founded in 1946.
Holy Rosary Colleges Foundation: private school at Calaba, San Isidro, Nueva Ecija.