The Legislative Districts of Isabela, namely the first, second, third, fourth, fifth and sixth are the representations of the Province of Isabela and the independent city of Santiago in the Philippine House of Representatives. 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. In 2016, it was redistricted into six (6) legislative districts.
Municipalities: Cabagan, Delfin Albano, Divilacan, Maconacon, Palanan, San Pablo, Santa Maria, Santo Tomas, Tumauini
Population (2015): 245,409
City: Ilagan City
Municipalities: Cabagan, Delfin Albano, Divilacan, Maconacon, Palanan, San Pablo, Santa Maria, Santo Tomas, Tumauini
Population (2015): 390,977
City: Ilagan City
Municipalities: Benito Soliven, Naguilian, Reina Mercedes, San Mariano
Population (2015): 289,462
Municipalities: Aurora, Benito Soliven, Burgos, Gamu, Mallig, Naguilian, Quezon, Quirino, Roxas, San Manuel, San Mariano
Population (2015): 380,090
City: Cauayan City
Municipalities: Alicia, Cabatuan, Luna
Population (2015): 259,766
City: Cauayan City
Municipalities: Alicia, Angadanan, Cabatuan, Luna, Reina Mercedes, San Guillermo, San Mateo
Population (2015): 414,530
City: Santiago City
Municipalities: Cordon, Jones, San Agustin
Population (2015): 246,302
City: Santiago City1
Municipalities: Cordon, Dinapigue, Echague, Jones, Ramon, San Agustin, San Isidro
Population (2015): 407,969
Municipalities: Aurora, Burgos, Gamu, Mallig, Quezon, Quirino, Roxas, San Manuel
Population (2015): 263,194
Municipalities: Angadanan, Dinapigue, Echague, San Guillermo, Ramon, San Isidro, San Mateo
Population (2015): 289,433
Legislative districts of Isabela Wikipedia (Text) CC BY-SA