Alilem is a philippine municipality in the province Ilocos Sur in Region I Ilocos Region which belongs to the Luzon group of islands. The municipality Alilem is seated about 79 km south of province capital City Of Vigan and about 261 km north of Philippine main capital Manila.
Alilem is a 4th class municipality. Regarding urbanization Alilem is classified as partly urban. Alilem occupies an area of 119.33 km². By the end of 2007 Alilem was the home of 6,217 residents. Thus by average 52.10 people are living on one km².
Administratively the Municipality of Alilem is subdivided into 9 barangays. One forms the center of the city wheras the other 8 are in the outlying areas. Some of them are even several kilometers away from the center of the Municipality. The most populous are Apang, Kiat, Batbato, Apaya, Amilongan, Daddaay, Anaao, Dalawa, Alilem Daya (Pob.).
Among the bigger cities and municipalities in the neighborhood of Alilem there are Calasiao (Pangasinan) 98 km south, City Of San Fernando (La Union) 37 km south-west, Baguio City (Benguet) 52 km south, La Trinidad (Benguet) 45 km south, Dagupan City (Pangasinan) 95 km south-south-west, Mangaldan (Pangasinan) 92 km south, Bauang (La Union) 44 km south-south-west, Binmaley (Pangasinan) 98 km south-south-west, City Of Alaminos (Pangasinan) 99 km south-west as well as 99 km south of Alilem the municipality Santa Barbara (Pangasinan).