Barangay Ambangonan

Situated in Rosario, La Union, Barangay Ambangonan is one of 33 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 Ambangonan had a population of 711. This made it the 31st largest of 33 barangays in Rosario by population, placing it among the smaller barangays of the municipality. Residents of Barangay Ambangonan accounted for approximately 1.18% of the total population of Rosario, which stood at 60,278 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay Ambangonan changed from 581 to 711, a shift of +22.4% over the five-year period. This places the barangay among those with growing populations in Rosario. The Philippine Statistics Authority classifies Barangay Ambangonan as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Rosario is a municipality comprising 33 barangays, and serves as the governing unit directly responsible for local services in Barangay Ambangonan, 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 Ambangonan ranks 463rd 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 Ambangonan 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.