Sigay is a fifth class municipality in the province of Ilocos Sur, Philippines. According to the 2015 census, it has a population of 2,737 people. Nestled near the Cordillera ranges, Sigay has crisp cool air and rustic scenery. Known to nature-lovers, adventurers, campers and mountaineers, the town attracts visitors with its version of the rice terraces, the 142 feet Aw-asen Falls, the kilometric hanging bridge, and its picturesque rivers. ^ Census of Population. "Region I ".