Maasin, officially the Municipality of Maasin, is a municipality in the province of Iloilo, Philippines. According to the 2020 census, it has a …Maasin, officially the Municipality of Maasin, is a municipality in the province of Iloilo, Philippines. According to the 2020 census, it has a population of 38,461 people. Maasin is 30 kilometres from Iloilo City.