Barangay San Mariano

Situated in Santa Marcela, Apayao, Barangay San Mariano is one of 13 barangays that make up the municipality within CAR.

According to the 2020 Philippine census, Barangay San Mariano had a population of 987. This made it the 6th largest of 13 barangays in Santa Marcela by population, placing it in the middle tier of the municipality. Residents of Barangay San Mariano accounted for approximately 7.41% of the total population of Santa Marcela, which stood at 13,317 in the same census year.

The barangay recorded 1,069 residents in the 2015 intercensal count and 987 residents in the 2020 Census — a net change of -7.7%, consistent with a contracting settlement. Barangay San Mariano is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Santa Marcela is a municipality comprising 13 barangays, and serves as the governing unit directly responsible for local services in Barangay San Mariano, including public health, sanitation, peace and order, and civil registration. Within the wider province of Apayao, which contains 133 barangays across its component cities and municipalities, Barangay San Mariano ranks 49th by 2020 population. Apayao is classified as a 3rd by the Bureau of Local Government Finance, a category that reflects the province's annual regular income.

Like every Philippine barangay, Barangay San Mariano 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.