Encarnación is a district and the capital city of Itapúa Department in Paraguay, located at the south-east of the department, on the right-hand (western) shore of the Paraná River, opposite Posadas, Argentina. The city has an area of 274 km2 and a population of 93,497, and the Greater Encarnacion area has a population of over 225,000 according to a 2020 estimate. Encarnación is the third-largest city of Paraguay. The city was originally named Nuestra Señora de la Anunciación de Itapúa, and is considered the capital of summer by most of its inhabitants.

The Argentina–Paraguay border is the line that limits the territories of Argentina and Paraguay. This boundary is solely defined by three major rivers: the Pilcomayo, Paraná and Paraguay, being one of the largest natural borders in the world. The capital of Paraguay, Asunción, lies on one of the banks of the Paraguay River, which borders Argentina. The capital of Argentina is Buenos Aires, which lies on one of the banks of the River Plate, made by major Paraguayan tributaries. Argentina is the country which Paraguay has the largest border with, being about 1,689 km long. It is Argentina's second largest border, after the Argentina–Chile border.