Boac, officially the Municipality of Boac, is a 1st class municipality and capital of the province of Marinduque, Philippines. According to the 2…Boac, officially the Municipality of Boac, is a 1st class municipality and capital of the province of Marinduque, Philippines. According to the 2020 census, it has a population of 57,283 people making the most populous town in Marinduque.