Barangay Casilagan

Barangay Casilagan is a small barangay in the municipality of Santa Cruz, located in the province of Ilocos Sur, in the Ilocos Region region of the Philippines.

According to the 2020 Philippine census, Barangay Casilagan had a population of 891. This made it the 20th largest of 49 barangays in Santa Cruz by population, placing it in the middle tier of the municipality. Residents of Barangay Casilagan accounted for approximately 2.15% of the total population of Santa Cruz, which stood at 41,366 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay Casilagan changed from 842 to 891, a shift of +5.8% over the five-year period. This places the barangay among those with growing populations in Santa Cruz. Barangay Casilagan is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Santa Cruz is a municipality comprising 49 barangays, and serves as the governing unit directly responsible for local services in Barangay Casilagan, 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 Casilagan ranks 318th 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 Casilagan 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.