Barangay Mainit Sur

Barangay Mainit Sur forms part of Perez, a municipality in Quezon, and is classified as a small barangay.

According to the 2020 Philippine census, Barangay Mainit Sur had a population of 1,425. This made it the 3rd largest of 14 barangays in Perez by population, placing it in the upper half of the municipality. Residents of Barangay Mainit Sur accounted for approximately 11.16% of the total population of Perez, which stood at 12,767 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay Mainit Sur changed from 1,365 to 1,425, a shift of +4.4% over the five-year period. This places the barangay among those with growing populations in Perez. Barangay Mainit Sur is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Perez is a municipality comprising 14 barangays, and serves as the governing unit directly responsible for local services in Barangay Mainit Sur, 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 Mainit Sur ranks 448th 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.

Like every Philippine barangay, Barangay Mainit Sur is led by an elected Punong Barangay (barangay captain) supported by seven Sangguniang Barangay members (kagawads), an SK Chairperson, a Barangay Secretary, and a Barangay Treasurer. The next Barangay and Sangguniang Kabataan Elections (BSKE) are scheduled for Monday, November 2, 2026, with officials serving four-year terms under Republic Act No. 12232.