City (pop., 1999 est.: city, 2,904,192; metro area, 12,423,000), capital of Argentina.
Located on an estuary of the Río de la Plata in east-central Argentina, about 130 mi (210 km) from the Atlantic Ocean, it is nevertheless a major port. First colonized by the Spanish in 1536, it was not permanently settled until 1580. It became the seat of the Viceroyalty of the Río de la Plata in 1776. In 1854 its residents drew up a constitution separate from those of the provinces and began fighting intermittently with the provinces over control of the Argentine government. After being made a federal district and Argentina's capital, it settled its wars with the provinces (1880) and by World War I (1914–18) had become a thriving port. The country's largest and most influential city, it is an important industrial and transportation centre.