Puerto Iguazú is a border city in the province of Misiones, Argentina. With a population of 82,227, it is the fourth largest city in the Province, afte…Puerto Iguazú is a border city in the province of Misiones, Argentina. With a population of 82,227, it is the fourth largest city in the Province, after Posadas, Oberá, and Eldorado. The world-renowned Iguazú Falls are only 18 kilometres away from the city, and as a result the city has developed much of its infrastructure around tourism.