Barangay San Ildefonso

Situated in Casiguran, Aurora, Barangay San Ildefonso is one of 24 barangays that make up the municipality within Central Luzon.

According to the 2020 Census of Population and Housing conducted by the Philippine Statistics Authority, Barangay San Ildefonso had a population of 1,118. This made it the 10th largest of 24 barangays in Casiguran by population, placing it in the middle tier of the municipality. Residents of Barangay San Ildefonso accounted for approximately 4.21% of the total population of Casiguran, which stood at 26,564 in the same census year.

Census comparisons between 2015 and 2020 show Barangay San Ildefonso moving from 1,115 residents to 1,118 residents, an intercensal change of +0.3%. The trajectory indicates a slowly expanding community. The Philippine Statistics Authority classifies Barangay San Ildefonso as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Casiguran is a municipality comprising 24 barangays, and serves as the governing unit directly responsible for local services in Barangay San Ildefonso, including public health, sanitation, peace and order, and civil registration. Within the wider province of Aurora, which contains 151 barangays across its component cities and municipalities, Barangay San Ildefonso ranks 79th by 2020 population. Aurora is classified as a 3rd by the Bureau of Local Government Finance, a category that reflects the province's annual regular income.

Like every Philippine barangay, Barangay San Ildefonso 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.