Barangay San Marcial

Barangay San Marcial forms part of San Isidro, a municipality in Abra, and is classified as a small barangay.

According to the 2020 Philippine census, Barangay San Marcial had a population of 623. This made it the 3rd largest of 9 barangays in San Isidro by population, placing it in the upper half of the municipality. Residents of Barangay San Marcial accounted for approximately 13.13% of the total population of San Isidro, which stood at 4,745 in the same census year.

The barangay recorded 619 residents in the 2015 intercensal count and 623 residents in the 2020 Census — a net change of +0.6%, consistent with a slowly expanding settlement. Barangay San Marcial is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

San Isidro is a municipality comprising 9 barangays, and serves as the governing unit directly responsible for local services in Barangay San Marcial, including public health, sanitation, peace and order, and civil registration. Within the wider province of Abra, which contains 303 barangays across its component cities and municipalities, Barangay San Marcial ranks 167th by 2020 population. Abra is classified as a 3rd 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.