Barangay San Guillermo

Classified as a small barangay, Barangay San Guillermo is one of the administrative divisions of San Jacinto in Pangasinan, Ilocos Region, Philippines.

According to the 2020 Census of Population and Housing conducted by the Philippine Statistics Authority, Barangay San Guillermo had a population of 855. This made it the 18th largest of 19 barangays in San Jacinto by population, placing it among the smaller barangays of the municipality. Residents of Barangay San Guillermo accounted for approximately 1.93% of the total population of San Jacinto, which stood at 44,351 in the same census year.

Census comparisons between 2015 and 2020 show Barangay San Guillermo moving from 920 residents to 855 residents, an intercensal change of -7.1%. The trajectory indicates a contracting community. The Philippine Statistics Authority classifies Barangay San Guillermo as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

San Jacinto is a municipality comprising 19 barangays, and serves as the governing unit directly responsible for local services in Barangay San Guillermo, 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 Guillermo ranks 1227th 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.

Like every Philippine barangay, Barangay San Guillermo 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.