In a land area of 10,664 square kilometers, the diocesan territory covers the entire civil province of Isabela. Isabela is the second largest province of the Philippines next to Palawan. It is located in the Cagayan Valley Region in Luzon. Its capital is Ilagan. It lies 398 kilometers northeast of Manila.
Isabela province has 35 municipalities (Alicia, Angadanan, Aurora, Benito Soliven, Burgos, Cabagan, Cabatuan, Cordon, Delfin Albanoremove space , Divilican, Echague, Gamu, Ilagan, Jones, Luna, Maconacon, Mallig, Naguilian, Palanan, Quezon, Quirino, Ramon, Reina Mercedes, Roxas, San Agustin, San Guillermo, San Isidro, San Miguel, San Mariano, San Mateo, San Pablo, Santa Maria, Santo Tomas and Tumauini) and 1,055 barangays and is divided into four congressional districts. Santiago is an independent-component city while Cauayan is a component city. Ilagan is the capital town while Cauayan is the industrial center.
Santiago City, the commercial center of Region 2, has been declared an independent-component city through a plebiscite on July 3, 1994 under Republic Act 7720. Cauayan City, the trading center in Isabela, is also a component city ratified in a majority vote on March 30, 2001.
As of year 2016 the total population of the diocese is 1,557,000 of which 80.10% are Catholics.
Diocese of Ilagan
Suffragan of Tugegarao
Created: Jan. 31, 1970
Erected: May 12, 1970
Comprises the entire civil Province of Isabela
Titular: St. Ferdinand, May 30
The Diocese of Ilagan was created on Jan. 31, 1970. It was canonically erected on May 12, 1970, with the Most Rev. Francisco R. Cruses, D.D as its first Bishop. Its titular patron is St. Ferdinand. It is a suffragan of the Archdiocese of Tuguegarao. The territorial jurisdiction of the diocese has a total land area of 10,644 square kilometers. Before its separation from the Diocese of Tuguegarao, which was one of the four new dioceses recognized by Pope Leo XIII (1878-1903) by the Bull Quae Mari Sinico and implemented by Pius X (1903-1914) through the Decretum Consistoriale on April 19, 1910, Isabela remained under the aegis of the Diocese of Tuguegarao.
Under the Diocese of Tuguegarao, the first appointed Vicar General was the diocese's own Msgr. Ricardo Jamias, D.P., S.T.L. who was also a member of the Council of Administrators, Pro-Synodal Examiners and Diocesan Directors.
On March 26, 1974, the Most Rev. Miguel G. Purugganan, D.D., a native of Cabagan, Isabela, succeeded the Most Rev. Francisco R. Cruces, D.D. as Bishop of the Diocese of Ilagan.
On Feb. 10 1997, the Most Rev. Sergio L. Utleg, D.D., a priest of the Archdiocese of Tuguegarao from Solana, Cagayan, was appointed Coadjutor Bishop of Ilagan. He was consecrated to the episcopacy on March 17, 1997. On July 26, 1999, becoming the third Bishop of the Diocese of Ilagan. After a decade of a Spiritual Father of Ilagan, the Bishop Sergio L. Utleg was transferred to the Diocese of Laoag.
On Jan. 15, 2007, Rt. Rev. Msgr. Marino D. Gatan, H.P. a native son of the town of Cabagan became the Diocesan Administrator while the Diocese of Ilagan became sede vacante.
On June 10, 2008, a year and a half after the Diocese was declared vacant, Pope Benedict XVI appointed Father Joseph Amangi Nacua, OFMCap., a Parish Priest of San Isidro Labrador Parish, Titay, Zamboanga-Sibugay, (Prelature of Ipil) as the fourth Bishop of the Diocese of Ilagan. He was ordained Bishop of Ilagan on Aug. 19, 2008 at St. Joseph the Worker Cathedral, Ipil, Zamboanga-Sibugay by Archbishop Diosdado Tamalayan, D.D. in the presence of Archbishop Edward Joseph Adams, D.D., Apostolic Nuncio to the Philippines.
Literacy rate (simple literacy) is 92.06 percent according to the government.
Isabela Day (May 1-11): Celebrates the founding of the Province and showcases each municipality's specialties.
Bambanti (Scarecrow) Festival (May 10): Celebrates the bountiful harvest of rice and corn and other agricultural products with street dances and a float parade
Feast of Our Lady of the Visitacion of Guibang (July 2)