Barangay Ambucao

Situated in Santiago, Ilocos Sur, Barangay Ambucao is one of 24 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 Ambucao had a population of 1,713. This made it the 2nd largest of 24 barangays in Santiago by population, placing it among the most populous barangays of the municipality. Residents of Barangay Ambucao accounted for approximately 8.80% of the total population of Santiago, which stood at 19,471 in the same census year.

Census comparisons between 2015 and 2020 show Barangay Ambucao moving from 1,709 residents to 1,713 residents, an intercensal change of +0.2%. The trajectory indicates a slowly expanding community. The Philippine Statistics Authority classifies Barangay Ambucao as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Santiago is a municipality comprising 24 barangays, and serves as the governing unit directly responsible for local services in Barangay Ambucao, including public health, sanitation, peace and order, and civil registration. Within the wider province of Ilocos Sur, which contains 768 barangays across its component cities and municipalities, Barangay Ambucao ranks 77th by 2020 population. Ilocos Sur 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.