Argentina occupies 2,780,400 square kilometers in southern South America, making it the eighth-largest country by land area. The territory extends 3,694 kilometers from La Quiaca at the Bolivian border to Ushuaia in Tierra del Fuego, spanning latitudes from 21 degrees south to 55 degrees south. This north-south extension crosses multiple climate zones from subtropical wetlands to subpolar forests. The country shares 11,968 kilometers of land borders with Chile to the west, Bolivia and Paraguay to the north, and Brazil and Uruguay to the northeast. The western border with Chile follows the Andes cordillera for approximately 5,308 kilometers, making it the third-longest international land boundary on Earth after the Canada-United States and Kazakhstan-Russia borders.
The Andes Mountains form the entire western margin of Argentina, rising abruptly from the Pacific coastal plain in Chile. Within Argentine territory, the cordillera varies dramatically in character from north to south. In the Puna de Atacama region of northwestern Argentina, the mountains form a high plateau between 3,000 and 4,000 meters elevation, punctuated by volcanic peaks exceeding 6,000 meters. This zone is among the driest places on Earth, receiving less than 50 millimeters of annual precipitation in some areas. Aconcagua reaches 6,961 meters in Mendoza Province, representing the highest elevation in both the Western and Southern Hemispheres. The mountain sits within the Principal Cordillera, a range that exceeds 6,000 meters at numerous points between latitudes 32 and 34 degrees south. South of Mendoza, the Andes decrease in elevation, falling below 4,000 meters in the Lake District around San Carlos de Bariloche and continuing to descend toward the southern terminus near Ushuaia, where peaks rarely exceed 2,500 meters.
The Pampas constitute a flat to gently rolling plain covering approximately 750,000 square kilometers in central Argentina. The region centers on Buenos Aires Province but extends into southern Córdoba, southern Santa Fe, eastern La Pampa, and small portions of Entre Ríos provinces. This grassland ecosystem developed on deep loess soils deposited during Pleistocene glacial periods, creating some of the most fertile agricultural land on the planet. The Humid Pampas, in the eastern portion receiving 600 to 1,200 millimeters of annual rainfall, support the majority of Argentina's grain and oilseed production. The Dry Pampas to the west transition gradually into semi-arid scrubland as precipitation decreases below 600 millimeters annually. The flatness is nearly absolute across vast areas—elevations vary by less than 100 meters over distances exceeding 400 kilometers in some sections. The Tandilia and Ventania ranges south of Buenos Aires city represent the only significant topographic relief, rising to 524 meters and 1,247 meters respectively. These ancient Precambrian formations predate the Andes by hundreds of millions of years.
Patagonia encompasses all Argentine territory south of the Río Colorado, approximately 760,000 square kilometers representing more than one quarter of the national landmass. The region divides into two distinct zones separated by the Andes. East of the cordillera, the Patagonian Steppe extends from the Atlantic coast to the mountain foothills as a series of basaltic plateaus descending in elevation from west to east. These tablelands, or mesetas, rise between 800 and 1,500 meters in the interior before dropping to near sea level at the Atlantic. The climate is cold semi-arid to arid, with precipitation ranging from 150 to 300 millimeters annually across most areas. Strong westerly winds blow nearly constantly, desiccating vegetation and creating erosion patterns across the exposed plateaus. The Valdés Peninsula extends 100 kilometers into the Atlantic in Chubut Province, forming two deep gulfs. The peninsula lies at or below sea level at several points, including a depression 40 meters below sea level representing the lowest continental point in South America.
West of the Patagonian Andes, a narrow strip of Chilean territory descends to the Pacific Ocean, but on the Argentine side the mountains transition abruptly to the steppe. The orographic effect creates extreme precipitation gradients—the western Andean slopes receive 2,000 to 4,000 millimeters annually while locations 50 kilometers east receive less than 300 millimeters. This moisture differential carved the lake district that extends from Neuquén through Río Negro and Chubut provinces. Nahuel Huapi, the largest lake in the region, covers 557 square kilometers at 767 meters elevation. The glacial lakes occupy troughs carved during Pleistocene glaciations when ice sheets extended far onto what is now the steppe. Subsequent deglaciation filled these basins with meltwater, creating the fingerlike lakes oriented east-west perpendicular to the Andean front.
Tierra del Fuego comprises all land south of the Strait of Magellan, with approximately 21,000 square kilometers under Argentine sovereignty and 29,000 square kilometers belonging to Chile. The international boundary divides the main island, Isla Grande de Tierra del Fuego, along a line running roughly north-south through the center. The Beagle Channel separates the main island from smaller southern islands including Navarino, which belongs to Chile. Argentine territory extends to Isla de los Estados, an uninhabited island 29 kilometers long lying 29 kilometers east of the Fuegan mainland. Ushuaia, at 54 degrees 48 minutes south latitude, functions as the provincial capital and southernmost city globally with population exceeding 50,000. The city occupies a north-facing slope at the southern foot of the Martial Range, positioned between mountains rising to 1,450 meters and the Beagle Channel. The terrain throughout Argentine Tierra del Fuego combines Andean foothills, glacially carved valleys, peat bogs, and southern beech forests that terminate abruptly where they meet the wind-scoured steppe.
The Gran Chaco occupies approximately 250,000 square kilometers in northern Argentina across portions of Formosa, Chaco, Santiago del Estero, and northern Santa Fe provinces. This low-lying subtropical plain extends north into Paraguay and Bolivia, forming one of South America's largest continuous forested regions. The Argentine portion receives 500 to 1,300 millimeters of annual precipitation concentrated in summer months, supporting dry forest and thorny scrubland vegetation. Rivers including the Pilcomayo, Bermejo, and Salado cross the region flowing southeast toward the Paraná, but most watercourses become intermittent during the winter dry season. The terrain is almost perfectly flat, sloping less than 20 meters per 100 kilometers in most areas. This minimal gradient causes rivers to shift course frequently and creates extensive wetlands during summer floods. Indigenous Wichí, Toba, and Mocoví peoples inhabited the region for thousands of years before Spanish colonization, subsisting through fishing, hunting, and gathering in an environment that resisted agricultural settlement until the twentieth century.
Mesopotamia describes the region between the Paraná and Uruguay rivers in northeastern Argentina, encompassing Entre Ríos and Corrientes provinces plus the province of Misiones. The name directly references the Greek meaning "between rivers" although the region bears no cultural or historical connection to the Middle Eastern Mesopotamia. The Paraná River forms the western boundary, running 3,998 kilometers from its headwaters in Brazil to its delta north of Buenos Aires. At its confluence with the Paraguay River at the Paraná's km 1,240 point, the combined flow exceeds 17,000 cubic meters per second during normal conditions. The Uruguay River defines the eastern margin of Mesopotamia, flowing 1,838 kilometers from Brazil through the Uruguay-Argentina border to its junction with the Paraná in the Río de la Plata estuary. Both rivers rise substantially during summer months when subtropical precipitation and snowmelt from southern Brazilian highlands create flood pulses that inundate low-lying areas.
The Iberá Wetlands occupy approximately 13,000 square kilometers in central Corrientes Province, forming one of the largest freshwater wetland systems in South America. The ecosystem consists of shallow lagoons, floating islands of vegetation, marshes, and seasonally flooded grasslands fed primarily by rainfall rather than river overflow. Water depths rarely exceed three meters even in permanent lagoons. The wetlands formed in a former channel of the Paraná River that was abandoned when the river shifted course during the Holocene. Poor drainage in the flat landscape allows water to accumulate in the shallow depression. The name Iberá derives from Guaraní words meaning "bright water" referring to the reflective quality of the lagoon surfaces. Native wildlife includes yacaré caimans, capybaras, marsh deer, and numerous bird species. Agricultural development eliminated much wetland area during the twentieth century, but approximately 7,000 square kilometers received provincial protection in 1983.
The Paraná Delta begins near the city of Diamante in Entre Ríos Province where the Paraná divides into multiple channels approximately 320 kilometers north of Buenos Aires. The delta extends downstream to the Río de la Plata, growing in width from 18 kilometers near its origin to 65 kilometers at its mouth. The deltaic region encompasses approximately 17,500 square kilometers of islands, channels, and wetlands. Sediment deposition advances the delta front into the Río de la Plata at approximately 70 meters per year, though rates vary considerably between different distributary channels. The islands consist primarily of sediment deposited during floods, building land surfaces that remain only one to three meters above normal river levels. Residents engage in fruit cultivation, forestry, and livestock grazing on the larger islands, accessing properties primarily by boat through the maze of channels.
The Río de la Plata estuary forms where the Paraná and Uruguay rivers converge, creating a funnel-shaped embayment that widens from 40 kilometers at its origin near Colonia del Sacramento to 220 kilometers between Punta del Este, Uruguay and Punta Rasa, Argentina. The estuary carries an average discharge of 22,000 cubic meters per second, making it the highest-discharge estuary entering the Atlantic from South America. Despite the massive flow, depths remain shallow—the natural channel rarely exceeds 10 meters deep and extensive dredging maintains navigable passages to Buenos Aires and Montevideo. The water is brackish rather than fully saline throughout most of the estuary, with ocean saltwater penetrating only the outer portions near the Atlantic. Sediment from upstream gives the water a characteristic brown color that extends well into the South Atlantic during flood periods. Buenos Aires and La Plata occupy the southern shore while Montevideo and other Uruguayan cities line the northern coast.
Northwestern Argentina encompasses the provinces of Jujuy, Salta, Tucumán, and Catamarca, presenting geography distinct from both the Pampas and Patagonia. The region contains three parallel north-south trending ranges separated by longitudinal valleys. The easternmost ranges, the Sierras Subandinas, rise abruptly from the Chaco plain to elevations of 2,000 to 3,000 meters, capturing moisture from easterly winds and supporting yungas cloud forest on their eastern slopes. The valleys between ranges descend to 1,000 to 1,500 meters elevation, creating semi-arid conditions suitable for viticulture and other intensive agriculture. The Calchaquí Valleys in Salta and Catamarca provinces extend more than 200 kilometers north-south at elevations between 1,500 and 2,000 meters, protected from both east and west by mountain barriers. The western cordillera rises to the Puna plateau, where elevations exceed 3,500 meters across extensive areas. Salta city sits at 1,187 meters elevation in the Lerma Valley, positioned between the subtropical lowlands to the east and high-elevation plateaus to the west.
The Quebrada de Humahuaca follows the Río Grande north from San Salvador de Jujuy toward the Bolivian border, rising from 1,260 meters at its southern end to approximately 3,000 meters near the village of Humahuaca. The valley cuts through sedimentary rock layers deposited over millions of years, creating dramatic color striations visible on the valley walls. The formation received UNESCO World Heritage designation in 2003 for its archaeological sites documenting 10,000 years of human occupation and its role as a trade route connecting the Andean highlands with the southern plains. Indigenous fortified settlements, or pucarás, occupy defensive positions on hilltops overlooking the valley floor. Spanish colonial churches from the seventeenth and eighteenth centuries stand in towns including Tilcara, Purmamarca, and Humahuaca. The valley remains an active agricultural zone, with farmers cultivating potatoes, maize, and vegetables in field systems that sometimes overlie pre-Hispanic agricultural terraces.
Salinas Grandes sits at 3,450 meters elevation on the border between Jujuy and Salta provinces, covering approximately 212 square kilometers. The salt flat formed in an endorheic basin where evaporation exceeds precipitation, concentrating dissolved minerals over thousands of years. The salt crust reaches depths of 30 centimeters in some areas, consisting primarily of sodium chloride with smaller quantities of other salts. Small-scale salt extraction operations employ traditional methods, cutting blocks from the surface and allowing them to dry before transport to markets. The brilliant white surface creates intense glare under the high-altitude sun. Route 52 crosses the salinas, connecting San Salvador de Jujuy with the Chilean border at Paso de Jama, a route used increasingly for commercial truck traffic between Atlantic and Pacific ports.
Mendoza Province contains the greatest concentration of high Andean peaks in Argentina, with 15 summits exceeding 6,000 meters elevation within provincial boundaries. Aconcagua attracts approximately 3,500 summit attempts annually, though success rates vary between 30 and 40 percent depending on route and conditions. The normal route via the northwest ridge requires no technical climbing but demands acclimatization to extreme altitude. The mountain was first climbed in 1897 by a European expedition led by British climber Edward FitzGerald with Swiss guide Matthias Zurbriggen. Earlier indigenous ascents likely occurred but lack documentation. The massif is volcanic in origin, formed by subduction of the Nazca Plate beneath the South American Plate. The Mendoza River originates from glacial meltwater on Aconcagua's slopes, flowing east to irrigate the agricultural zones that support the provincial economy.
The Cuyo region comprises Mendoza, San Juan, and San Luis provinces in west-central Argentina, positioned in the rain shadow of the Andes. Annual precipitation ranges from 200 to 250 millimeters in valley floors, insufficient for non-irrigated agriculture. Rivers fed by Andean snowmelt including the Mendoza, Tunuyán, Diamante, Atuel, San Juan, and Jáchal provide water for extensive irrigation systems developed beginning in the colonial period. These oases support intensive viticulture—Mendoza Province alone contains approximately 150,000 hectares of vineyards producing 70 percent of Argentine wine. The vines grow at elevations between 600 and 1,500 meters in the main production zones, with some vineyards exceeding 2,000 meters in the Calchaquí Valleys. Soil consists primarily of alluvial deposits from Andean erosion, providing excellent drainage. Temperature variation between day and night reaches 15 to 20 degrees Celsius during the growing season, slowing ripening and enhancing flavor development in grapes.
San Juan Province immediately north of Mendoza contains the Ullum and Caracoles valleys, where viticulture occurs at elevations between 600 and 1,400 meters. The province produces approximately 15 percent of Argentine wine, specializing in white varieties including Torrontés. Talampaya National Park in northwestern San Juan protects 2,150 square kilometers of desert landscape characterized by red sandstone cliffs rising 150 meters above the canyon floor. The rock formations accumulated as river sediments during the Triassic period 250 million years ago, later uplifted and eroded into the present topography. Petroglyphs and grinding stones document indigenous occupation extending back at least 2,500 years. The park adjoins Ischigualasto Provincial Park across the border in San Juan Province, together forming a UNESCO World Heritage site for their paleontological significance.
Los Glaciares National Park encompasses 7,269 square kilometers in Santa Cruz Province along the eastern Andean slope. The park contains 47 glaciers descending from the Southern Patagonian Ice Field, which covers approximately 16,800 square kilometers spanning the Chile-Argentina border. Perito Moreno Glacier terminates at Lago Argentino, the largest lake in Argentina at 1,466 square kilometers. The glacier front extends 5 kilometers wide and rises 60 meters above lake level, with an additional 170 meters of ice below the waterline. The terminus advances approximately 2 meters per day in the central section, though the overall position has remained relatively stable over the past century while most Patagonian glaciers retreat. Periodically the glacier advances across the lake to form an ice dam against the Magellan Peninsula, blocking drainage from the Rico Arm of Lago Argentino. Water accumulates behind the dam until pressure causes the ice to rupture, releasing the impounded water in a dramatic outburst that has occurred more than 30 times since records began in 1917. The most recent rupture occurred in March 2018.