Alilem, officially the Municipality of Alilem, is a municipality in the province of Ilocos Sur, Philippines. According to the 2020 census, it has a pop…Alilem, officially the Municipality of Alilem, is a municipality in the province of Ilocos Sur, Philippines. According to the 2020 census, it has a population of 7,361 people. Alilem is 106 kilometres from Vigan and 323 kilometres from Manila.