South Florida encompasses a three-county area of the southeastern part of the U.S. state of Florida. The metropolitan area covers the counties of Miami-Dade, Broward, and Palm Beach. The three counties are the three most populous in Florida. The term "South Florida" is roughly synonymous with the Gold Coast. The principal cities include Miami, Fort Lauderdale, and West Palm Beach. The Florida Keys are also included in the metropolitan area at times.

Because the population of South Florida is largely confined to a strip of land between the Atlantic Ocean and the Everglades, the Miami urbanized area (that is, the area of contiguous urban development) is about 110 miles (180 km) long (north to south), but never more than 20 miles (32 km) wide, and in some areas only 5 miles (8.0 km) wide (east to west). South Florida is longer than any other urbanized area in the United States except for the New York metropolitan area. It was the eighth most densely populated urbanized area in the United States in the 2000 census. As of the 2000 census, the urbanized area had a land area of 1,116 square miles ( 2,890.7 square kilometers), with a population of 4,919,036, for a population density of 4,407.4 per square mile (1,701.7 per square kilometer). Miami and Hialeah (the second largest city in the metropolitan area) had population densities of more than 10,000 per square mile (more than 3,800 per square kilometer). The Miami Urbanized Area was the fifth largest Urbanized Area (but 7th largest metropolitan area) in the United States in the 2000 census.

The Miami metro area also includes several urban clusters (UCs) as of the 2000 Census which are not part of the Miami Urbanized Area. These are the Belle Glade UC, population 24,218, area 20,717,433 square metres and population density of 3027.6 per square mile; Key Biscayne UC, population 10,513, area 4,924,214 square metres and population density of 5529.5 per square mile; Redland UC, population 3,936, area 10,586,212 square metres and population density of 963.0 per square mile; and West Jupiter UC, population 8,998, area 24,737,176 square metres and population density of 942.1 per square mile.