Barangay San Marcos

Situated in Santo Tomas, Pangasinan, Barangay San Marcos is one of 10 barangays that make up the municipality within Ilocos Region.

According to the 2020 Census of Population and Housing conducted by the Philippine Statistics Authority, Barangay San Marcos had a population of 881. This made it the 9th largest of 10 barangays in Santo Tomas by population, placing it among the smaller barangays of the municipality. Residents of Barangay San Marcos accounted for approximately 5.92% of the total population of Santo Tomas, which stood at 14,878 in the same census year.

The barangay recorded 975 residents in the 2015 intercensal count and 881 residents in the 2020 Census — a net change of -9.6%, consistent with a contracting settlement. The Philippine Statistics Authority classifies Barangay San Marcos as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Santo Tomas is a municipality comprising 10 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 Pangasinan, which contains 1,364 barangays across its component cities and municipalities, Barangay San Marcos ranks 1219th by 2020 population. Pangasinan is classified as a 1st 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.