Legislative districts of Isabela

The legislative districts of Isabela are the representations of the province of Isabela and the independent component city of Santiago in the various national legislatures of the Philippines. The province and the city are currently represented in the lower house of the Congress of the Philippines through their first, second, third, fourth, fifth, and sixth congressional districts.

History
The province was represented as a lone legislative district until 1972. It was part of the representation of Region II from 1978 to 1984, and from 1984 to 1986, it elected 3 assemblymen at-large. In 1986, it was redistricted into four legislative districts.

On September 27, 2018, President Rodrigo Duterte signed Republic Act No. 11080, increasing the legislative districts from four to six and reapportioned the district assignments of cities and municipalities.

1st District

 * City: Ilagan
 * Municipalities: Cabagan, Delfin Albano, Divilacan, Maconacon, San Pablo, Santa Maria, Santo Tomas, Tumauini
 * Population (2020): 399,196

2nd District

 * Municipalities: Benito Soliven, Gamu, Naguilian, Palanan, Reina Mercedes, San Mariano
 * Population (2020): 199,903

3rd District

 * Municipalities: Alicia, Angadanan, Cabatuan, Ramon, San Mateo
 * Population (2020): 282,027

4th District

 * City: Santiago
 * Municipalities: Cordon, Dinapigue, Jones, San Agustin
 * Population (2020): 268,602

5th District

 * Municipalities: Aurora, Burgos, Luna, Mallig, Quezon, Quirino, Roxas, San Manuel
 * Population (2020): 267,550

6th District

 * City: Cauayan
 * Municipalities: Echague, San Guillermo, San Isidro
 * Population (2020): 279,772

1st District

 * City: Ilagan (became a city in 2012)
 * Municipalities: Cabagan, Delfin Albano, Divilacan, Maconacon, Palanan, San Pablo, Santa Maria, Santo Tomas, Tumauini

2nd District

 * Municipalities: Aurora, Benito Soliven, Burgos, Gamu, Mallig, Naguilian, Quezon, Quirino, Roxas, San Manuel, San Mariano

3rd District

 * City: Cauayan (became a city in 2001)
 * Municipalities: Alicia, Angadanan, Cabatuan, Luna, Reina Mercedes, San Guillermo, San Mateo

4th District

 * City: Santiago (became a city in 1994)
 * Municipalities: Cordon, Dinapigue, Echague, Jones, Ramon, San Agustin, San Isidro

Notes

Lone District (defunct)
Notes