Barangay Matandang Gasan

Barangay Matandang Gasan forms part of Gasan, a municipality in Marinduque, and is classified as a small barangay.

According to the 2020 Philippine census, Barangay Matandang Gasan had a population of 1,830. This made it the 7th largest of 25 barangays in Gasan by population, placing it in the upper half of the municipality. Residents of Barangay Matandang Gasan accounted for approximately 5.06% of the total population of Gasan, which stood at 36,197 in the same census year.

Census comparisons between 2015 and 2020 show Barangay Matandang Gasan moving from 1,581 residents to 1,830 residents, an intercensal change of +15.7%. The trajectory indicates a growing community. Barangay Matandang Gasan is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Gasan is a municipality comprising 25 barangays, and serves as the governing unit directly responsible for local services in Barangay Matandang Gasan, 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 Matandang Gasan ranks 31st 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.

Like every Philippine barangay, Barangay Matandang Gasan 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.