Ilagan, the most populous city in the Isabela, is politically subdivided into 91 barangays.
These barangays are grouped into four clusters: Poblacion, Eastern, Western, and San Antonio.
List below shows the latest population census (as of 2020), economic class, land area, and the current Barangay Captains (Punong Barangay), and SK chairpersons serving their terms from 2023 to 2025, considered as the shortest term of office.
[2] Errol John R. Nebalasca from barangay Santa Isabel Sur, is the current president of SK Federation.
Also includes Barangay Justice System as the Lupon Tagapamayapa.