Miami Beach is a coastal resort city in Miami-Dade County, Florida, United States. It was incorporated on March 26, 1915. The municipality is located on a series of natural and man-made barrier islands between the Atlantic Ocean and Biscayne Bay, the latter of which separates the Beach from Miami city proper. The neighborhood of South Beach, comprising the southernmost 2.5 square miles (6.5 km²) of Miami Beach, along with downtown Miami and the port, collectively form the commercial center of South Florida.