Barangay Santa Isabel Sur

Barangay Santa Isabel Sur forms part of City of Ilagan, a city in Isabela, and is classified as a large barangay.

According to the 2020 Census of Population and Housing conducted by the Philippine Statistics Authority, Barangay Santa Isabel Sur had a population of 5,002. This made it the 3rd largest of 91 barangays in City of Ilagan by population, placing it among the most populous barangays of the city. Residents of Barangay Santa Isabel Sur accounted for approximately 3.16% of the total population of City of Ilagan, which stood at 158,218 in the same census year.

Census comparisons between 2015 and 2020 show Barangay Santa Isabel Sur moving from 4,612 residents to 5,002 residents, an intercensal change of +8.5%. The trajectory indicates a growing community. The Philippine Statistics Authority classifies Barangay Santa Isabel Sur as urban, reflecting the density and built-up character of the area.

City of Ilagan is a city comprising 91 barangays, and serves as the governing unit directly responsible for local services in Barangay Santa Isabel Sur, including public health, sanitation, peace and order, and civil registration. Within the wider province of Isabela, which contains 1,055 barangays across its component cities and municipalities, Barangay Santa Isabel Sur ranks 31st by 2020 population. Isabela is classified as a 1st by the Bureau of Local Government Finance, a category that reflects the province's annual regular income.

Barangay Santa Isabel Sur is governed by an elected Sangguniang Barangay composed of a Punong Barangay and seven kagawads, with the Sangguniang Kabataan representing the youth. The next BSKE, set for Monday, November 2, 2026, will elect officials to four-year terms as provided under Republic Act No. 12232.