San Guillermo

San Guillermo
Municipality of San Guillermo
Map of Isabela with San Guillermo highlighted
Interactive map of San Guillermo
San Guillermo
Location within the Philippines
Coordinates: 16°43′28″N 121°48′36″E / 16.7244°N 121.81°E / 16.7244; 121.81
CountryPhilippines
RegionCagayan Valley
ProvinceIsabela
District 6th district
FoundedJune 17, 1967
Named afterEugenio Guillermo
Barangays26 (see Barangays)
Government
 • TypeSangguniang Bayan
 • MayorFelipe N. Guyud, Jr.
 • Vice MayorBernadine M. Lucas
 • RepresentativeFaustino A. Dy V
 • Electorate13,806 voters (2025)
Area
 • Total
325.49 km2 (125.67 sq mi)
Elevation
88 m (289 ft)
Highest elevation
128 m (420 ft)
Lowest elevation
43 m (141 ft)
Population
 (2024 census)
 • Total
21,043
 • Density64.650/km2 (167.44/sq mi)
 • Households
4,989
Economy
 • Income class4th municipal income class
 • Poverty incidence
22.09
% (2021)
 • Revenue₱ 205.6 million (2022)
 • Assets₱ 497.9 million (2022)
 • Expenditure₱ 128.8 million (2022)
 • Liabilities₱ 119.3 million (2022)
Service provider
 • ElectricityIsabela 1 Electric Cooperative (ISELCO 1)
Time zoneUTC+8 (PST)
ZIP code
3308
PSGC
IDD:area code+63 (0)78
Native languagesIlocano
Tagalog
Websitewww.sanguillermo-isabela.gov.ph

San Guillermo (Spanish for Saint William), officially the Municipality of San Guillermo, is a municipality in the province of Isabela, Philippines. According to the 2024 census, it has a population of 21,043 people.