Entre Ríos Province in the context of Center Region, Argentina

The Uruguay River (Spanish: Río Uruguay [ˈri.o wɾuˈɣwaj]; Portuguese: Rio Uruguai [ˈʁi.u uɾuˈɡwaj]) is a major river in South America. It flows from north to south and forms parts of the boundaries of Brazil, Argentina and Uruguay, separating some of the Argentine provinces of the Mesopotamia from the other two countries. It passes between the states of Santa Catarina and Rio Grande do Sul in Brazil; forms the eastern border of the provinces of Misiones, Corrientes and Entre Ríos in Argentina; and makes up the western borders of the departments of Artigas, Salto, Paysandú, Río Negro, Soriano and Colonia in Uruguay.

Y Wladfa (Welsh pronunciation: [ə ˈwladva], 'The Colony'), also occasionally Y Wladychfa Gymreig (Welsh pronunciation: [ə wlaˈdəχva ɡəmˈreiɡ], 'The Welsh Settlement'), refers to the establishment of settlements by Welsh colonists and immigrants in the Argentine Patagonia, beginning in 1865, mainly along the coast of the lower Chubut Valley. In 1881, the area became part of the Chubut National Territory of Argentina which, in 1955, became Chubut Province.

In the 19th and early 20th centuries, the Argentine government encouraged emigration from Europe to populate Argentina and south Patagonia particularly, which until the Conquest of the Desert had sparsely rural and coastal settlements. Between 1856 and 1875, 34 settlements of immigrants of various nationalities were established in Santa Fe and Entre Ríos. In addition to the main colony in Chubut, a smaller colony was set up in Santa Fe by 44 Welsh people who left Chubut, and another group settled at Coronel Suárez in southern Buenos Aires Province.

Corrientes (Spanish pronunciation: [koˈrjentes], lit. ‘currents’ or ‘streams’; Guarani: Taragui), officially the Province of Corrientes (Spanish: Provincia de Corrientes; Guarani: Taragui Tetãmini) is a province in northeast Argentina, in the Mesopotamia region. It is surrounded by (from the north, clockwise): Paraguay, Misiones, Brazil, Uruguay, and the provinces of Entre Rios, Santa Fe and Chaco.

The Argentina–Uruguay border is a line of 579 km marked by the Uruguay River, and is the border between Argentina and Uruguay. It starts in a triple border Argentina-Uruguay-Brazil, at the mouth of the Quaraí River in the Uruguay. The course follows the Uruguay river, passing west of the Uruguayan departments of Artigas, Salto, Paysandu, Rio Negro, Soriano and Colonia and the Argentine provinces of Corrientes, Entre Rios and Buenos Aires, until the confluence of the Uruguay and the Paraná rivers into the Rio de la Plata.

The Charrúa are an Indigenous people or Indigenous Nation of the Southern Cone in present-day Uruguay and the adjacent areas in Argentina (Entre Ríos) and Brazil (Rio Grande do Sul). They were a semi-nomadic people who sustained themselves mainly through hunting and gathering. Since resources were not permanent in every region, they would constantly be on the move. Rain, drought, and other environmental factors determined their movement. For this reason they are often classified as seasonal nomads.

The Charrúa people were massacred in a campaign in 1831 by the Uruguayan Army known as the Massacre of Salsipuedes. Though largely erased from modern histories, some communities of the Charrúa survived outside of Uruguay in Argentina and Brazil. It is believed that there are approximately between 160,000 and 300,000 individuals in Uruguay, Argentina, and Brazil today who are descendants of surviving Charrúa. Contemporary descendants of the Charrúa have created organizations and advocate for the memory of the Indigenous people.

The Mesopotamia or Región Mesopotámica is the humid and verdant area of northeast Argentina, comprising the provinces of Misiones, Entre Ríos, and Corrientes. The landscape and its characteristics are dominated by two rivers: the Paraná and the Uruguay.

When Spanish settlers came to the area, the two parallel rivers and the lush area between them drew comparisons to Mesopotamia (Greek: Μεσοποταμία "land between rivers") in modern-day Iraq, and it was decided that the Argentine region be named after the Iraqi region. The region shares many of its ecological features with neighboring regions of Argentina and with parts of Brazil, Paraguay, and Uruguay.

Buenos Aires, officially the Buenos Aires Province, is the largest and most populous Argentine province. It takes its name from the city of Buenos Aires, the capital of the country, which used to be part of the province and the province's capital until it was federalized in 1880. Since then, in spite of bearing the same name, the province does not include Buenos Aires city, though it does include all other parts of the Greater Buenos Aires metropolitan region, which include approximately three-fourths of the conurbation's population. The capital of the province is the city of La Plata, founded in 1882.

It is bordered by the provinces of Entre Ríos to the northeast, Santa Fe to the north, Córdoba to the northwest, La Pampa to the west, Río Negro to the south and west and the Autonomous City of Buenos Aires to the northeast. Uruguay is just across the Rio de la Plata to the northeast, and both are on the coast of the Atlantic Ocean to the east. Almost the entire province is part of the Pampas geographical region, with the extreme south often considered part of the Patagonia region.

Córdoba (Spanish pronunciation: [ˈkoɾðoβa]) is a province of Argentina, located in the center of the country. Its neighboring provinces are (clockwise from the north) Santiago del Estero, Santa Fe, Buenos Aires, La Pampa, San Luis, La Rioja, and Catamarca. Together with Santa Fe and Entre Ríos, the province is part of the economic and political association known as the Center Region.

Córdoba is the second-most populous Argentine province, with 3,978,984 inhabitants, and the fifth by size, at about 165,321 km (63,831 sq mi). Almost 41% of its inhabitants reside in the capital city, Córdoba, and its surroundings, making it the second most populous metro area in Argentina.