Miami ( /maɪæmi/ or /maɪæmə/) is a city located on the Atlantic coast in southeastern Florida and the county seat of Miami-Dade County, the most populous county in Florida and the eighth-most populous county in the United States with a population of 2,500,625. The 42nd largest city proper in the United States, with a population of 399,457, it is the principal, central, and most populous city of the South Florida metropolitan area, the most populous metropolis in the Southeastern United States. According to the US Census Bureau, Miami's metro area is the seventh most populous and fifth-largest urban area in the United States, with an estimated population of 5,547,051 in 2009.
Miami is a major center and a leader in finance, commerce, culture, media, entertainment, the arts, and international trade. In 2010, Miami ranked seventh in the United States in terms of finance, commerce, culture, entertainment, fashion, education, and other sectors. It ranked thirty-third among global cities.
In 2008, Forbes magazine ranked Miami "America's Cleanest City", for its year-round good air quality, vast green spaces, clean drinking water, clean streets and city-wide recycling programs. According to a 2009 UBS study of 73 world cities, Miami was ranked as the richest city in the United States, and the world's fifth-richest city in terms of purchasing power.