Quirino, officially the Municipality of Quirino, is a municipality in the province of Isabela, Philippines. According to the 2020 census, it ha…Quirino, officially the Municipality of Quirino, is a municipality in the province of Isabela, Philippines. According to the 2020 census, it has a population of 25,023 people. Quirino was named in honor of Elpidio Quirino, the president.