Barangay Arnap

Situated in San Ildefonso, Ilocos Sur, Barangay Arnap is one of 15 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 Arnap had a population of 244. This made it the 14th largest of 15 barangays in San Ildefonso by population, placing it among the smaller barangays of the municipality. Residents of Barangay Arnap accounted for approximately 2.98% of the total population of San Ildefonso, which stood at 8,190 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay Arnap changed from 218 to 244, a shift of +11.9% over the five-year period. This places the barangay among those with growing populations in San Ildefonso. The Philippine Statistics Authority classifies Barangay Arnap as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

San Ildefonso is a municipality comprising 15 barangays, and serves as the governing unit directly responsible for local services in Barangay Arnap, 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 Arnap ranks 737th 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.

Like every Philippine barangay, Barangay Arnap 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.