Mamasapano, officially the Municipality of Mamasapano, is a 5th class municipality in the province of Maguindanao del Sur, Philippines. Acc…Mamasapano, officially the Municipality of Mamasapano, is a 5th class municipality in the province of Maguindanao del Sur, Philippines. According to the 2020 census, it has a population of 27,807 people.