Pamplona, officially the Municipality of Pamplona, is a municipality in the province of Cagayan, Philippines. According to the 2020 census, it has a population of 24,781 people. Pamplona is the result of the merging of two villages during the Spanish era - Abulacan and Masi. Abulacan was founded by the ecclesiastical authorities on April 30, 1757, with San Juan Nepomuceno as the patron saint. Sometime in 1842, Vicar Pedro Montenegro, O.P. convinced the people to unite the two towns. The vicar named it "Pamplona" in memory of his hometown Pamplona in Spain.