Barangay San Isidro

Classified as a very small barangay, Barangay San Isidro is one of the administrative divisions of Santa Cruz in Marinduque, MIMAROPA Region, Philippines.

According to the 2020 Philippine census, Barangay San Isidro had a population of 458. This made it the 45th largest of 55 barangays in Santa Cruz by population, placing it among the smaller barangays of the municipality. Residents of Barangay San Isidro accounted for approximately 0.84% of the total population of Santa Cruz, which stood at 54,692 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay San Isidro changed from 453 to 458, a shift of +1.1% over the five-year period. This places the barangay among those with slowly expanding populations in Santa Cruz. Barangay San Isidro is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Santa Cruz is a municipality comprising 55 barangays, and serves as the governing unit directly responsible for local services in Barangay San Isidro, including public health, sanitation, peace and order, and civil registration. Within the wider province of Marinduque, which contains 218 barangays across its component cities and municipalities, Barangay San Isidro ranks 178th by 2020 population. Marinduque is classified as a 4th 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.