Miami Dade County is a county located in the southeastern part of the state of Florida. Miami Dade County is the eighth most populous county in the nation. Its county seat is Miami. Miami-Dade County is one of three counties that comprise the South Florida metropolitan area. Miami Dade County has a total area of approximately 2,431 square miles of which 80% is land and 20% water. As of the 2000 census, there were 2,253,362 people, 776,774 households, and 548,402 families residing in Miami Dade County, FL.