Aparri, officially the Municipality of Aparri, is a 1st class municipality in the province of Cagayan, Philippines. According to the 2020 census, it h…Aparri, officially the Municipality of Aparri, is a 1st class municipality in the province of Cagayan, Philippines. According to the 2020 census, it has a population of 68,839 people. It sits at the mouth of the Cagayan River, the longest river in the Philippines. Aparri is 101 kilometres from Tuguegarao and 582 kilometres from Manila.