|Region :||Ilocos region|
August 1, 2015 census
|Population density :||267 inhabitants per km²|
|Area :||2,579.6 km²|
|Governor :||Deogracias Victor B. Savellano|
|- Highly urbanized cities||0|
|- provincial cities||2|
|- electoral districts||2|
|Location of Ilocos Sur in the Philippines|
The province is bordered by the provinces of Abra in the north, Mountain Province in the east, and La Union and Benguet in the south. In the west the province borders on the South China Sea and in the east on the Philippine Cordillera . The Abra flows into the sea south of Vigan City . The southern border to La Union is based on the Amburayan river to its mouth.
Cities and municipalities
Ilocos Sur is divided into 2 cities and 32 municipalities, which in turn are divided into 768 barangays .
In the course of the British invasion of the Philippines at the end of the Seven Years' War , there were uprisings in the province in 1762/63. These were led by Diego Silang and his wife Gabriela . Her greatest achievement was the capture of the city of Vigan.