Barangay Sisim Alto

Barangay Sisim Alto is a small barangay in the municipality of Tumauini, located in the province of Isabela, in the Cagayan Valley region of the Philippines.

According to the 2020 Philippine census, Barangay Sisim Alto had a population of 1,233. This made it the 28th largest of 46 barangays in Tumauini by population, placing it in the middle tier of the municipality. Residents of Barangay Sisim Alto accounted for approximately 1.74% of the total population of Tumauini, which stood at 70,743 in the same census year.

The barangay recorded 1,070 residents in the 2015 intercensal count and 1,233 residents in the 2020 Census — a net change of +15.2%, consistent with a growing settlement. Barangay Sisim Alto is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Tumauini is a municipality comprising 46 barangays, and serves as the governing unit directly responsible for local services in Barangay Sisim Alto, 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 Sisim Alto ranks 528th 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.