Reina Mercedes, officially the Municipality of Reina Mercedes, is a municipality in the province of Isabela, Philippines. According to the 2…Reina Mercedes, officially the Municipality of Reina Mercedes, is a municipality in the province of Isabela, Philippines. According to the 2020 census, it has a population of 27,900 people. The town derived its name in honor of Mercedes of Orléans, Queen of Spain. Coupled with the province's name "Isabela", named after Isabella II, Queen Regnant of Spain, the town's address of "Reina Mercedes, Isabela" is the most regnant address in the Philippines.