Biri is a fifth class municipality in the province of Northern Samar, Philippines. According to the 2010 census, it has a population of 10,987 people. The municipality is facing Pacific Ocean to the east and San Bernardino Strait to the west. It consists of several islands off the northern coast of Samar Island, the largest of which is Biri Island. Other larger islands are Talisay, Magasang, and Cagnipa.