Barangay San Marcos

Barangay San Marcos is a mid-sized barangay in the municipality of Agoo, located in the province of La Union, in the Ilocos Region region of the Philippines.

According to the 2020 Philippine census, Barangay San Marcos had a population of 2,191. This made it the 7th largest of 49 barangays in Agoo by population, placing it in the upper half of the municipality. Residents of Barangay San Marcos accounted for approximately 3.32% of the total population of Agoo, which stood at 66,028 in the same census year.

The barangay recorded 2,072 residents in the 2015 intercensal count and 2,191 residents in the 2020 Census — a net change of +5.7%, consistent with a growing settlement. Barangay San Marcos is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Agoo is a municipality comprising 49 barangays, and serves as the governing unit directly responsible for local services in Barangay San Marcos, including public health, sanitation, peace and order, and civil registration. Within the wider province of La Union, which contains 576 barangays across its component cities and municipalities, Barangay San Marcos ranks 82nd by 2020 population. La Union 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 Marcos 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.