Barangay San Antonio

Barangay San Antonio forms part of Roxas, a municipality in Isabela, and is classified as a mid-sized barangay.

According to the 2020 Census of Population and Housing conducted by the Philippine Statistics Authority, Barangay San Antonio had a population of 3,531. This made it the 8th largest of 26 barangays in Roxas by population, placing it in the upper half of the municipality. Residents of Barangay San Antonio accounted for approximately 5.36% of the total population of Roxas, which stood at 65,839 in the same census year.

The barangay recorded 3,454 residents in the 2015 intercensal count and 3,531 residents in the 2020 Census — a net change of +2.2%, consistent with a growing settlement. The Philippine Statistics Authority classifies Barangay San Antonio as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Roxas is a municipality comprising 26 barangays, and serves as the governing unit directly responsible for local services in Barangay San Antonio, 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 San Antonio ranks 74th 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.

The barangay's legislative and executive affairs are handled by a Punong Barangay and the Sangguniang Barangay, elected nationwide during the Barangay and SK Elections. The next BSKE is scheduled for Monday, November 2, 2026, following the synchronized election schedule set by COMELEC Resolution No. 11191.