Barangay San Isidro Zone III

Barangay San Isidro Zone III is a small barangay in the City of Tayabas, located in the province of Quezon, in the CALABARZON region of the Philippines.

According to the 2020 Philippine census, Barangay San Isidro Zone III had a population of 1,167. This made it the 25th largest of 66 barangays in City of Tayabas by population, placing it in the middle tier of the city. Residents of Barangay San Isidro Zone III accounted for approximately 1.04% of the total population of City of Tayabas, which stood at 112,658 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay San Isidro Zone III changed from 1,384 to 1,167, a shift of -15.7% over the five-year period. This places the barangay among those with contracting populations in City of Tayabas. Barangay San Isidro Zone III is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

City of Tayabas is a city comprising 66 barangays, and serves as the governing unit directly responsible for local services in Barangay San Isidro Zone III, including public health, sanitation, peace and order, and civil registration. Within the wider province of Quezon, which contains 1,242 barangays across its component cities and municipalities, Barangay San Isidro Zone III ranks 521st by 2020 population. Quezon 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.