Barangay Mambulo Viejo

Classified as a mid-sized barangay, Barangay Mambulo Viejo is one of the administrative divisions of Libmanan in Camarines Sur, Bicol Region, Philippines.

According to the 2020 Philippine census, Barangay Mambulo Viejo had a population of 2,506. This made it the 9th largest of 75 barangays in Libmanan by population, placing it in the upper half of the municipality. Residents of Barangay Mambulo Viejo accounted for approximately 2.22% of the total population of Libmanan, which stood at 112,994 in the same census year.

The barangay recorded 2,341 residents in the 2015 intercensal count and 2,506 residents in the 2020 Census — a net change of +7.0%, consistent with a growing settlement. Barangay Mambulo Viejo is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Libmanan is a municipality comprising 75 barangays, and serves as the governing unit directly responsible for local services in Barangay Mambulo Viejo, including public health, sanitation, peace and order, and civil registration. Within the wider province of Camarines Sur, which contains 1,063 barangays across its component cities and municipalities, Barangay Mambulo Viejo ranks 240th by 2020 population. Camarines Sur 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.