Barangay San Agustin

Situated in Isabela, Negros Occidental, Barangay San Agustin is one of 30 barangays that make up the municipality within Western Visayas.

According to the 2020 Philippine census, Barangay San Agustin had a population of 3,602. This made it the 4th largest of 30 barangays in Isabela by population, placing it in the upper half of the municipality. Residents of Barangay San Agustin accounted for approximately 5.58% of the total population of Isabela, which stood at 64,516 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay San Agustin changed from 3,778 to 3,602, a shift of -4.7% over the five-year period. This places the barangay among those with contracting populations in Isabela. Barangay San Agustin is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Isabela is a municipality comprising 30 barangays, and serves as the governing unit directly responsible for local services in Barangay San Agustin, including public health, sanitation, peace and order, and civil registration. Within the wider province of Negros Occidental, which contains 662 barangays across its component cities and municipalities, Barangay San Agustin ranks 277th by 2020 population. Negros Occidental is classified as a 1st by the Bureau of Local Government Finance, a category that reflects the province's annual regular income.

Like every Philippine barangay, Barangay San Agustin is led by an elected Punong Barangay (barangay captain) supported by seven Sangguniang Barangay members (kagawads), an SK Chairperson, a Barangay Secretary, and a Barangay Treasurer. The next Barangay and Sangguniang Kabataan Elections (BSKE) are scheduled for Monday, November 2, 2026, with officials serving four-year terms under Republic Act No. 12232.