Barangay IV (Pob.)

Situated in San Mateo, Isabela, Barangay IV (Pob.) is one of 33 barangays that make up the municipality within Cagayan Valley.

According to the 2020 Census of Population and Housing conducted by the Philippine Statistics Authority, Barangay IV (Pob.) had a population of 3,134. This made it the 4th largest of 33 barangays in San Mateo by population, placing it among the most populous barangays of the municipality. Residents of Barangay IV (Pob.) accounted for approximately 4.70% of the total population of San Mateo, which stood at 66,663 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay IV (Pob.) changed from 3,130 to 3,134, a shift of +0.1% over the five-year period. This places the barangay among those with slowly expanding populations in San Mateo. The Philippine Statistics Authority classifies Barangay IV (Pob.) as urban, reflecting the density and built-up character of the area.

San Mateo is a municipality comprising 33 barangays, and serves as the governing unit directly responsible for local services in Barangay IV (Pob.), 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 IV (Pob.) ranks 92nd 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.

Like every Philippine barangay, Barangay IV (Pob.) 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.