Posadas is the capital city of the Argentine province of Misiones, in its south, at the far north-west of the country on the left bank of the Paraná River, opposite Encarnación, Paraguay. The city has an area of 965 square kilometres (373 sq mi) and a population of 324,756, and the Greater Posadas area has a population of over 359,609 according to a 2017 estimate.

Misiones is one of the 23 provinces of Argentina, located in the northeastern corner of the country in the Mesopotamia region. It is surrounded by Paraguay to the northwest, Brazil to the north, east and south, and Corrientes Province of Argentina to the southwest.