Barangay Casiaman

Barangay Casiaman forms part of Bacnotan, a municipality in La Union, and is classified as a small barangay.

According to the 2020 Census of Population and Housing conducted by the Philippine Statistics Authority, Barangay Casiaman had a population of 941. This made it the 18th largest of 47 barangays in Bacnotan by population, placing it in the middle tier of the municipality. Residents of Barangay Casiaman accounted for approximately 2.12% of the total population of Bacnotan, which stood at 44,388 in the same census year.

Census comparisons between 2015 and 2020 show Barangay Casiaman moving from 869 residents to 941 residents, an intercensal change of +8.3%. The trajectory indicates a growing community. The Philippine Statistics Authority classifies Barangay Casiaman as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Bacnotan is a municipality comprising 47 barangays, and serves as the governing unit directly responsible for local services in Barangay Casiaman, 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 Casiaman ranks 380th 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 Casiaman 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.