Ilagan town was  called  “Bolo”  by its native Gaddang settlers during the pre-Spanish conquest era. The cultural shock brought about by the Spanish regime propelled the natives to dissent which resulted to the Gaddang Revolution. Giving in to the natives, the Spaniards  exempted them from paying tax tributes for three years. Upon the efforts of Fr. Pedro Jimenez in 1678, the natives re-established their settlement on the east side of the river, thereby giving the legendary name for Ilagan which is the reverse of the word “Nagali” meaning “transfer”.

The Dominicans  accepted the settlement as an ecclesiastical mission on May 4, 1686 and  gave the name San Fernando de Ilagan in honor of its Patron Saint, St. Ferdiand.

Various tribes inhabited the valley in prosperity. The area from Tuguegarao down to Ilagan and Gamu was once the Irrayas. Unfortunately, the Irraya language and  culture became extinct following the enforcement of Ibanag language which was preferred by the Spaniards in 1752.

Ilagan became one of the largest  producers of tobacco during the Spanish time. The Tobacco Monopoly have caused the valley to languish in poverty from 1785 to 1797. The lifting of the monopoly was caused by the heavy loss incurred by the government. A Royal Decree  released in 1882  totally abolished the monopoly and attracted foreign capitalist to invest in the country. In Ilagan, the Compania General de Tabacos de Filipinas or the Tabacalera was established in 1881 and produced the famous La FLor de Isabela which was the largest company of its kind in the world at that time. The Tabacalera acquired two haciendas in Ilagan: the Hacienda San Antonio and Hacienda Sta. Isabela.

Documents  show that during the Spanish time, a Royal Decree was issued in May 1856 creating the Province of Isabela.

The province was reorganized as a province under the American regime through Act No. 210  passed in August 24, 1901. Ilagan’s town mayor,  RafaelMaramag was named as the first  Provincial Governor.

Ilagan was declared a third class component city on August 11, 2012 by virtue of Republic Act 10169 signed by President Benigno A. Aquino III under the leadership of Mayor Josemarie L. Diaz.

Ilagan is now the fourth city of Region 2 and the third city of the Province of Isabela. It holds the record of the highest turn out of voters in a plebiscite  winning 96% of the votes cast.

It is the provincial capital and the largest city in the Province of Isabela in terms of land area, and the fourth largest city in the country, after Davao, Puerto Princesa and Zamboanga City. Composed of 91 barangays with an area of 1,166.26 square kilometers, Ilagan enjoys dry season from December to April and rainy season for the rest of the year.

Majority of the people in Ilagan are Ilocanos and Ibanags. Other ethnic groups are Itawes and Gaddangs while Dumagats also carry on a nomadic life in the mountains. Farming is the main source  of income followed by furniture making while others engaged in trading and livestock production.

ILAGAN CITY

1. ILAGAN SANCTUARY is located within the Fuyot National Park and offers caves, swimming pools with 8.5 PH level, a waterfalls, petting zoo, picnic areas, boat, horseback and bicycle rides and the first  Zipline in the region believed to be the fastest with a length of 350 meters and a speed of 85 kph.

2. BALAY NA MAGUILI and Friendship Hall located beside the Rizal’s Park and is the headquarters of Stewards and Friends  ofIlagan Incorporated, an NGO assisting the LGU in its socio-tourism efforts.  The BalaynaMaguili is an arts hall where music lessons are taught to children. The Chapel inside the compound is a well-preserved 18th century structure.

3. ST. FERDINAND PARISH is known to house one of the oldest bells in the region. The church is dedicated to the Patron Saint, San Fernando. The church is located in the heart of the city and stands beside the St. Ferdinand  Collage

4. BUTAKA SHRINE is located along the Maharlika Highway, is also known as the Freedom Park where various groups exercise their Freedom of Expression. It also houses the world’s biggest Butaka which was brought to Intramuros, Manila during the first WOW Philippines exhibit.  Built at a cost of P175,000.00 for 29 days with a total of 1,762 board feet of seasoned narra, 1,740 foot-1 inch diameter of rattan; it is 11.4 feet tall, 9.70 feet wide and 20.8 feet long and weighs 2,368 kilos.

5. ILAGAN COCA COLA PLANT is one of the industrial complexes in the region frequented by excursionists to learn about the mechanized  processing of one of the country’s favorite soft drinks.

6. OLD CAPITOL BUILDING was once the seat of Power in the Province of Isabela. It is now being used to showcase the history of Isabela in a mini museum.

7. ISABELA PROVINCIAL CAPITOL in Brgy. Alibagu is the seat of power of the present day Isabela. It houses the offices of various national  line agencies. Infront of the capitol is the Sky Park which is an open air amphitheater recommended for evening activities.

8. ISABELA MUSEUM AND LIBRARY  was inaugurated last May 11, 1999 and is housed at the old capitol building in Ilagan. It is the repository and custodian of the rich historical and cultural heritage of Isabelinos. It features a gallery exhibit-collection of artifacts, fossils, heirloom pieces, visual arts, dioramas and other historical documents. It is open on weekdays.

MAMMANGI Festival – celebrated during the last week of May; an Ybnag word meaning the harvest or planting of corn. It honors the farmers who are the real foundation of Ilagan’s economy and is celebrated as a thanksgiving activity for a good harvest.