Dade County is also often referred to as Miami-Dade County (voters actually changed the name in 1997 to take advantage of the global recognition of the Miami name). Whichever name you use, the county is located in southeastern Florida against the Atlantic Ocean. This is the most populated county in Florida and the eighth most populous county in the United States. Miami-Dade County contains 1,946 square miles of land area and 485 square miles of water surface. The county seat is Miami. Dade County was founded on January 18, 1836. The county was named in honor of Major Francis L. Dade, a soldier killed during the Second Seminole War at what is now Dade Battlefield

Miami-Dade County is heavily urbanized with 35 incorporated towns and cities and many other built-up unincorporated areas. However, the Redland area of southern Miami-Dade County is still quite agricultural and the western part of the county extends into Everglades National Park and tends to be quite unpopulated. East of mainland Miami is Biscayne National Park.

Miami-Dade County was the scene of the costliest natural disaster in the history of the United States (until Hurricane Katrina came ashore in 2005): the passage of Hurricane Andrew on August 24, 1992. Hurricane Andrew remade much of south Florida, including a huge swath of destruction that was laid down just south of Miami itself. Estimated cost: $25 billion in the county alone.

Companies like Burger King, Brightstar Corporation, Latin Flavors, Ryder, Norwegian Cruise Line and Intradeco Holdings have their head corporate offices located in unincorporated areas of Miami-Dade County. The main Latin America offices of Hewlett-Packard Corporation are also in unincorporated Miami-Dade County. Miami International Airport is also in an unincorporated part of the county, with the headquarters of IBC Airways, Arrow Air and Florida West International Airways on the airport grounds.

More than 2/3 of the residents of Miami-Dade County speak a language other than English when at home.