Downtown Miami is an urban residential neighborhood, which is based around the Central Business District of Miami, Miami-Dade County, and South Florida in the United States. Brickell Avenue and Biscayne Boulevard are the main north-south roads, and Flagler Street is the main east-west road. The neighborhood is defined by the Miami Downtown Development Authority (DDA) as the -area east of Interstate 95 between the Rickenbacker Causeway to the south and Julia Tuttle Causeway to the north.