Barangay Casini

Barangay Casini forms part of Irosin, a municipality in Sorsogon, and is classified as a small barangay.

According to the 2020 Philippine census, Barangay Casini had a population of 1,106. This made it the 22nd largest of 28 barangays in Irosin by population, placing it among the smaller barangays of the municipality. Residents of Barangay Casini accounted for approximately 1.87% of the total population of Irosin, which stood at 59,267 in the same census year.

Census comparisons between 2015 and 2020 show Barangay Casini moving from 1,155 residents to 1,106 residents, an intercensal change of -4.2%. The trajectory indicates a contracting community. Barangay Casini is officially classified as rural, a designation applied to barangays with lower population density and predominantly non-built-up land use.

Irosin is a municipality comprising 28 barangays, and serves as the governing unit directly responsible for local services in Barangay Casini, including public health, sanitation, peace and order, and civil registration. Within the wider province of Sorsogon, which contains 541 barangays across its component cities and municipalities, Barangay Casini ranks 297th by 2020 population. Sorsogon is classified as a 2nd by the Bureau of Local Government Finance, a category that reflects the province's annual regular income.

Like every Philippine barangay, Barangay Casini 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.