Santa Lucia, officially the Municipality of Santa Lucia, is a municipality in the province of Ilocos Sur, Philippines. According to the 2020 census…Santa Lucia, officially the Municipality of Santa Lucia, is a municipality in the province of Ilocos Sur, Philippines. According to the 2020 census, it has a population of 25,966 people. The town celebrates its annual fiesta on December 13, the feast of its patroness, Saint Lucy.