Barangay San Isidro I

Barangay San Isidro I forms part of Paombong, a municipality in Bulacan, and is classified as a mid-sized barangay.

According to the 2020 Philippine census, Barangay San Isidro I had a population of 3,427. This made it the 7th largest of 14 barangays in Paombong by population, placing it in the middle tier of the municipality. Residents of Barangay San Isidro I accounted for approximately 6.15% of the total population of Paombong, which stood at 55,696 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay San Isidro I changed from 3,641 to 3,427, a shift of -5.9% over the five-year period. This places the barangay among those with contracting populations in Paombong. Barangay San Isidro I is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Paombong is a municipality comprising 14 barangays, and serves as the governing unit directly responsible for local services in Barangay San Isidro I, including public health, sanitation, peace and order, and civil registration. Within the wider province of Bulacan, which contains 569 barangays across its component cities and municipalities, Barangay San Isidro I ranks 348th by 2020 population. Bulacan 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 San Isidro I 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.