Barangay San Mariano

Situated in Roxas, Oriental Mindoro, Barangay San Mariano is one of 20 barangays that make up the municipality within MIMAROPA Region.

According to the 2020 Philippine census, Barangay San Mariano had a population of 4,798. This made it the 4th largest of 20 barangays in Roxas by population, placing it in the upper half of the municipality. Residents of Barangay San Mariano accounted for approximately 8.15% of the total population of Roxas, which stood at 58,849 in the same census year.

Census comparisons between 2015 and 2020 show Barangay San Mariano moving from 4,475 residents to 4,798 residents, an intercensal change of +7.2%. The trajectory indicates a growing community. Barangay San Mariano is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Roxas is a municipality comprising 20 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 Oriental Mindoro, which contains 426 barangays across its component cities and municipalities, Barangay San Mariano ranks 23rd by 2020 population. Oriental Mindoro 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 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.