Barangay Antagan I

Barangay Antagan I forms part of Tumauini, a municipality in Isabela, and is classified as a mid-sized barangay.

According to the 2020 Philippine census, Barangay Antagan I had a population of 3,293. This made it the 1st largest of 46 barangays in Tumauini by population, placing it among the most populous barangays of the municipality. Residents of Barangay Antagan I accounted for approximately 4.65% of the total population of Tumauini, which stood at 70,743 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay Antagan I changed from 3,004 to 3,293, a shift of +9.6% over the five-year period. This places the barangay among those with growing populations in Tumauini. Barangay Antagan I is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Tumauini is a municipality comprising 46 barangays, and serves as the governing unit directly responsible for local services in Barangay Antagan I, 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 Antagan I ranks 82nd 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 Antagan I 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.