Buenos AiresBue·nos Ai·res
- seaport & capital of Argentina, on the Río de la Plata within a federal district: 77 sq mi (199 sq km)
- province of E Argentina, on the Atlantic: 118,754 sq mi (307,572 sq km); cap. La Plata
- lake in the S Andes, on the Chilean-Argentine border: 865 sq mi (2,240 sq km)
The capital and largest city of Argentina, in the eastern part of the country on the Río de la Plata. Founded by the Spanish in 1536, it became the national capital in 1862. The highly industrialized city is also a major port.x
- The capital city of Argentina.