Irosin

Irosin, officially the Municipality of Irosin (Southern Sorsoganon: Bungto san Irosin; Waray: Bungto han Irosin, Tagalog: Bayan ng Irosin), is a municipality in the province of Sorsogon, Philippines.

Irosin
Municipality
Municipality of Irosin
Irosin Beacon with Mount Bulusan in the background
Flag
Map of Sorsogon with Irosin highlighted
OpenStreetMap
Irosin Location within the Philippines
Coordinates: 12°42′18″N 124°01′55″E
Country	Philippines
Region	Bicol Region
Province	Sorsogon
District	2nd district
Barangays	28 (see Barangays)
Government  [1]
• Type	Sangguniang Bayan
• Mayor	Alfredo J. Cielo Jr.
• Vice Mayor	Christian D. Lim
• Representative	Manuel L. Fortes Jr.
• Municipal Council	Members Agustin E. Delmonte III Virgilio M. Gabito Irvin Karl S. Fortes Reynaldo P. Lascano Jr. Mercy Donna D. Balmes Ansam J. Bringuela Antonio G. Gajo Jhumer B. Ong
• Electorate	41,494 voters (2025)
Area [2]
• Total	149.87 km2 (57.87 sq mi)
Elevation	168 m (551 ft)
Highest elevation	791 m (2,595 ft)
Lowest elevation	20 m (70 ft)
Population  (2024 census)[3]
• Total	59,540
• Density	400/km2 (1,000/sq mi)
• Households	12,753
Economy
• Income class	2nd municipal income class
• Poverty incidence	26.41 % (2021)[4]
• Revenue	₱ 312.5 million (2022)
• Assets	₱ 609.6 million (2022)
• Expenditure	₱ 275.9 million (2022)
• Liabilities	₱ 272 million (2022)
Service provider
• Electricity	Sorsogon 1 Electric Cooperative (SORECO 1)
Time zone	UTC+8 (PST)
ZIP code	4707
PSGC	0506209000
IDD : area code	+63 (0)56
Native languages	Sorsogon language Tagalog
Website	www.irosin.gov.ph

History

Irosin frequently experienced erosion due to river inundations. On December 24, 1933, massive flooding caused numerous fatalities. To prevent the violent surge of the river from eroding the town's mainland, a concrete river control dike was constructed in 1937 under Mayor Felipe Santiago and Congressman Norberto Roque.^{[5][better source needed]}

Contemporary period

On April 10, 1989, Irosin was defended by military and police forces, led by Lieutenant Antonio Dy, against approximately 200 communist rebels of the New People's Army, which resulted in 20 rebel casualties; along with the deaths of three female civilians in the crossfire.^[6] Dy later received the "Medalya ng Kagitingan" Award in August for leading his 13 policemen to defend Irosin's municipal hall.^[7]

The local tourism industry has significant potential, as ecological tourism is a global trend and the national government aims to develop Bicol as a major tourist hub. Given its variety of natural tourist spots and strategic location, Irosin serves as a convergence area for both foreign and domestic tourists and visitors.^[8]

Geography

Climate

Climate data for Irosin, Sorsogon
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Mean daily maximum °C (°F)	27 (81)	28 (82)	29 (84)	31 (88)	31 (88)	30 (86)	29 (84)	29 (84)	29 (84)	29 (84)	29 (84)	28 (82)	29 (84)
Mean daily minimum °C (°F)	22 (72)	21 (70)	22 (72)	23 (73)	24 (75)	25 (77)	25 (77)	25 (77)	25 (77)	24 (75)	23 (73)	23 (73)	24 (74)
Average precipitation mm (inches)	65 (2.6)	44 (1.7)	42 (1.7)	39 (1.5)	87 (3.4)	150 (5.9)	184 (7.2)	153 (6.0)	163 (6.4)	154 (6.1)	127 (5.0)	100 (3.9)	1,308 (51.4)
Average rainy days	13.9	9.2	11.0	12.5	19.6	24.3	26.5	25.0	25.5	24.4	19.4	15.1	226.4
Source: Meteoblue (modeled/calculated data, not measured locally)[9]

Political geography

Irosin is the only landlocked municipality in Sorsogon province.

Irosin is politically subdivided into 28 barangays, each consisting of puroks, and some with sitios.

• Bagsangan
• Bacolod (Poblacion)
• Batang
• Bolos
• Buenavista
• Bulawan
• Carriedo
• Casini
• Cawayan
• Cogon
• Gabao
• Gulang-Gulang
• Gumapia
• Santo Domingo (Lamboon)
• Liang
• Macawayan
• Mapaso
• Monbon
• Patag
• Salvacion
• San Agustin (Poblacion)
• San Isidro (Palogtok)
• San Juan (Poblacion)
• San Julian (Poblacion)
• San Pedro (Poblacion)
• Tabon-Tabon
• Tinampo
• Tongdol

Demographics

Population census of Irosin

Year	Pop.	±% p.a.
1903	8,644	—
1918	14,775	+3.64%
1939	17,017	+0.68%
1948	19,317	+1.42%
1960	23,134	+1.51%
1970	27,953	+1.91%
1975	30,989	+2.09%
1980	34,978	+2.45%
1990	37,887	+0.80%
1995	41,005	+1.49%
2000	45,507	+2.26%
2007	49,968	+1.30%
2010	51,777	+1.30%
2015	56,662	+1.73%
2020	59,267	+0.95%
2024	59,540	+0.11%
Source: Philippine Statistics Authority[10][11][12][13][14]

Economy

Poverty incidence of Irosin

10 20 30 40 50 2000 48.63 2003 44.69 2006 33.40 2009 34.18 2012 28.45 2015 37.34 2018 32.64 2021 26.41 Source: Philippine Statistics Authority[15][16][17][18][19][20][21][22]

Education

Tertiary education

Irosin is home to Veritas College of Irosin and the Irosin Institute of Science and Technology, the latter accredited by the Technical Education and Skills Development Authority (TESDA).^[23]