Barangay Santiago Sur

Barangay Santiago Sur forms part of Caba, a municipality in La Union, and is classified as a mid-sized barangay.

According to the 2020 Census of Population and Housing conducted by the Philippine Statistics Authority, Barangay Santiago Sur had a population of 2,082. This made it the 3rd largest of 17 barangays in Caba by population, placing it in the upper half of the municipality. Residents of Barangay Santiago Sur accounted for approximately 9.01% of the total population of Caba, which stood at 23,119 in the same census year.

The barangay recorded 1,969 residents in the 2015 intercensal count and 2,082 residents in the 2020 Census — a net change of +5.7%, consistent with a growing settlement. The Philippine Statistics Authority classifies Barangay Santiago Sur as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Caba is a municipality comprising 17 barangays, and serves as the governing unit directly responsible for local services in Barangay Santiago Sur, 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 Santiago Sur ranks 94th 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.

Barangay Santiago Sur 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.