Miami-Dade County is a county located in the southeastern part of the U.S. state of Florida. The county had a population of 2,701,767 as of the 2020 census, making it the most populous county in Florida and the seventh-most populous county in the United States. It is also Florida's third largest county in terms of land area, with 1,946 square miles (5,040 km2). The county seat is Miami, the core of the nation's ninth largest and world's 34th largest metropolitan area with a 2020 population of 6.138 million people.