Odiongan, officially the Municipality of Odiongan, is a 1st class municipality in the province of Romblon, Philippines. According to the 2020 censu…Odiongan, officially the Municipality of Odiongan, is a 1st class municipality in the province of Romblon, Philippines. According to the 2020 census, it has a population of 49,284 people. It is composed of 25 barangays.