Sibalom River  Sibalom River is the longest river in Antique province in Panay island in the Philippines. With a total length of and a drainage basin covering , it is the largest river system in Antique, located in Sibalom. Along with its main tributaries Mao-it River and Tipulu-an River, it forms the Tipulu-an and Mao-it River Watershed Forest Reserve (now known as Sibalom Natural Park) which was proclaimed a natural park on 23 April 2000. The river's watershed is considered as one of the last remaining lowland rainforests on Panay.