Barangay San Mariano

Classified as a small barangay, Barangay San Mariano is one of the administrative divisions of Lal-Lo in Cagayan, Cagayan Valley, Philippines.

According to the 2020 Philippine census, Barangay San Mariano had a population of 1,773. This made it the 7th largest of 35 barangays in Lal-Lo by population, placing it in the upper half of the municipality. Residents of Barangay San Mariano accounted for approximately 3.64% of the total population of Lal-Lo, which stood at 48,733 in the same census year.

Census comparisons between 2015 and 2020 show Barangay San Mariano moving from 1,521 residents to 1,773 residents, an intercensal change of +16.6%. 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.

Lal-Lo is a municipality comprising 35 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 Cagayan, which contains 820 barangays across its component cities and municipalities, Barangay San Mariano ranks 245th by 2020 population. Cagayan is classified as a 1st by the Bureau of Local Government Finance, a category that reflects the province's annual regular income.

Barangay San Mariano 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.