Pilcomayo River in the context of "Wichí"

Asunción (English: /ɑːˌsuːnsiˈoʊn, ˌɑːsuːnˈsjoʊn/, Spanish: [asunˈsjon]; Guarani: "Paraguay") is the capital and the largest city of Paraguay. The city stands on the eastern bank of the Paraguay River, almost at the confluence of this river with the Pilcomayo River. The Paraguay River and the Bay of Asunción in the northwest separate the city from the Occidental Region of Paraguay and from Argentina in the south part of the city. The rest of the city is surrounded by the Central Department.

Asunción is one of the oldest cities in South America and the longest continually inhabited area in the Río de la Plata Basin; for this reason it is known as "the Mother of Cities". From Asunción, Spanish colonial expeditions departed to found other cities, including the second foundation of Buenos Aires, that of other important cities such as Villarrica, Corrientes, Santa Fe, Córdoba, Santa Cruz de la Sierra and 65 more. According to the 2022 Paraguayan Census, Asunción has 462,241 inhabitants, while its metropolitan area (known as Greater Asunción) exceeds 2.3 million inhabitants, making it the most densely populated area in Paraguay, and also the most productive as it concentrates 70% of the National GDP. Asunción is the third most populated "jurisdiction" or "political division" in the country, surpassed by the Central and Alto Paraná departments.

The Argentine Northwest (Spanish: Noroeste argentino, NOA) is a geographic and historical region of Argentina comprising the provinces of Catamarca, Jujuy, La Rioja, Salta, Santiago del Estero and Tucumán. It borders Bolivia to the north, Chile to the west, the Northeast region to the east, the Center region to the south, and the Cuyo region to the southwest.

The region extends primarily over the Andes Mountains and their adjacent valleys, encompassing a diverse range of landscapes. The region's main geographic features are the Puna, the Calchaquí Valleys, the Yungas, and the Argentine portion of the Chaco Plains. Major rivers in the region include the Bermejo River, the Salí-Dulce River, and the Pilcomayo River.