The Buenos Aires Central Business District is the main commercial centre of Buenos Aires, Argentina, though not an official city ward. While the barrios of Puerto Madero and Retiro house important business complexes and modern high-rise architecture, the area traditionally known as Microcentro (Spanish: Microcenter) is located within San Nicolás and Monserrat, roughly coinciding with the area around the historic center of the Plaza de Mayo. The Microcentro has a wide concentration of offices, service companies and banks, and a large circulation of pedestrians on working days. Another name given to this unofficial barrio is La City, which refers more precisely to an even smaller sector within the Microcentro, where almost all the banking headquarters of the country are concentrated.
The area was the site of the first European settlement in what later became Buenos Aires. Its south–north axis runs along Leandro Alem Avenue, from Belgrano Avenue in the south to Retiro railway station in the north, and its east–west axis runs from the Buenos Aires Ecological Reserve to Ninth of July Avenue. The district is centered around the San Nicolás ward, and includes the northern section of Montserrat, the section of Retiro south of Santa Fe Avenue, and the section of Puerto Madero west of the Buenos Aires Docklands.
The district is the financial, corporate, and cultural hub of Buenos Aires, and of Argentina. The economy of Buenos Aires was the 13th largest among the world's cities in 2006 at US$245 billion in purchasing power parity, which, based on the population of that year, translates into US21,500 per capita. The Buenos Aires Human Development Index (0.925 in 1998) is likewise high by international standards.
The Port of Buenos Aires is one of the busiest in South America; navigable rivers by way of the Río de la Plata connect the port to northeastern Argentina, Brazil, Uruguay and Paraguay. As a result, it serves as the distribution hub for a vast area of the south-eastern region of the South American continent.