Miami is a coastal city in the U.S. state of Florida. It is the second-most populous city in Florida, with a population of 442,241 at the 2020 cens…Miami is a coastal city in the U.S. state of Florida. It is the second-most populous city in Florida, with a population of 442,241 at the 2020 census. The Miami metropolitan area in South Florida has an estimated 6.46 million residents and is the sixth-largest metropolitan area in the United States. Miami has the third-largest skyline in the U.S. with over 300 high-rises, 70 of which exceed 491 ft. It is the county seat of Miami-Dade County.