Barangay Biga Occidental

Barangay Biga Occidental is a small barangay in the municipality of Santo Tomas, located in the province of Isabela, in the Cagayan Valley region of the Philippines.

According to the 2020 Philippine census, Barangay Biga Occidental had a population of 724. This made it the 14th largest of 27 barangays in Santo Tomas by population, placing it in the middle tier of the municipality. Residents of Barangay Biga Occidental accounted for approximately 2.95% of the total population of Santo Tomas, which stood at 24,528 in the same census year.

Census comparisons between 2015 and 2020 show Barangay Biga Occidental moving from 744 residents to 724 residents, an intercensal change of -2.7%. The trajectory indicates a contracting community. Barangay Biga Occidental is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Santo Tomas is a municipality comprising 27 barangays, and serves as the governing unit directly responsible for local services in Barangay Biga Occidental, including public health, sanitation, peace and order, and civil registration. Within the wider province of Isabela, which contains 1,055 barangays across its component cities and municipalities, Barangay Biga Occidental ranks 814th by 2020 population. Isabela is classified as a 1st by the Bureau of Local Government Finance, a category that reflects the province's annual regular income.

The barangay's legislative and executive affairs are handled by a Punong Barangay and the Sangguniang Barangay, elected nationwide during the Barangay and SK Elections. The next BSKE is scheduled for Monday, November 2, 2026, following the synchronized election schedule set by COMELEC Resolution No. 11191.