Barangay San Isidro Sur (Pob.)

Classified as a small barangay, Barangay San Isidro Sur (Pob.) is one of the administrative divisions of Lagonoy in Camarines Sur, Bicol Region, Philippines.

According to the 2020 Philippine census, Barangay San Isidro Sur (Pob.) had a population of 670. This made it the 32nd largest of 38 barangays in Lagonoy by population, placing it among the smaller barangays of the municipality. Residents of Barangay San Isidro Sur (Pob.) accounted for approximately 1.18% of the total population of Lagonoy, which stood at 56,714 in the same census year.

Census comparisons between 2015 and 2020 show Barangay San Isidro Sur (Pob.) moving from 733 residents to 670 residents, an intercensal change of -8.6%. The trajectory indicates a contracting community. Barangay San Isidro Sur (Pob.) is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Lagonoy is a municipality comprising 38 barangays, and serves as the governing unit directly responsible for local services in Barangay San Isidro Sur (Pob.), 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 San Isidro Sur (Pob.) ranks 908th 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.

Barangay San Isidro Sur (Pob.) is governed by an elected Sangguniang Barangay composed of a Punong Barangay and seven kagawads, with the Sangguniang Kabataan representing the youth. The next BSKE, set for Monday, November 2, 2026, will elect officials to four-year terms as provided under Republic Act No. 12232.