Miami Dade County is home to 2,253,362 people, 776,774 households, and 548,402 families residing in the county. As of the 2000 census the population density is 447/km2 (1,158/mi2). There are 852,278 housing units at an average density of 169/km2 (438/mi2). The racial makeup of the county is 69.70% White, 29.29% Black (a large part of which are of Caribbean descent), 0.19% Native American , 1.41% Asian, 0.04% Pacific Islander, 4.58% from other races, and 3.79% from two or more races. 55.32% of the population are Hispanic or Latino of any race. Non-Hispanic whites make up 13.67% of the population. 50% of the county residents were born outside the United States, while 67% of the population speaks a language other than English at home.

According to the U.S. Census Bureau, the county has a total area of 6,297 km2 (2,431 mi2). 5,040 km2 (1,946 mi2) of it is land and 1,257 km2 (485 mi2) of it is water. The total area is 19.96% water, most of which is Biscayne Bay. The bay is divided from the Atlantic Ocean by the many barrier isles along the coast, one of which is where well-known Miami Beach is located, along with the South Beach Art Deco district.

There are 776,774 households out of which 33.80% have children under the age of 18 living with them, 47.70% are married couples living together, 17.20% have a female householder with no husband present, and 29.40% are non-families. 23.30% of all households are made up of individuals and 8.60% have someone living alone who is 65 years of age or older. The average household size is 2.84 and the average family size is 3.35.

The median income for a household in the county is $35,966, and the median income for a family is $40,260. Males have a median income of $30,120 versus $24,686 for females. The per capita income for the county is $18,497. 18.00% of the population and 14.50% of families are below the poverty line. Out of the total population, 22.90% of those under the age of 18 and 18.90% of those 65 and older are living below the poverty line.

Miami-Dade County is comprised of thirty-four other incorporated municipalities, including: Miami Beach, Aventura, Bal Harbour, Bay Harbor Island, Biscayne Park, Coral Gables, Cutler Ridge, Doral, El Portal, Florida City, Golden Beach, Hialeah, Hialeah Gardens, Homestead, Indian Creek, Islandia, Key Biscayne, Medleym Miami Gardens, Miami Lakes, Miami Shores, Miami Springs, North Bay Village, North Miami, North Miami Beach, Opa-Locka, Palmetto Bay, Pinecrest, South Miami, Sunny Isles, Surfisde, Sweetwater, Virginia Gardens, and west Miami.

Neighboring areas include: Broward County, East: North Atlantic Ocean, South: Florida Bay, Monroe County, and Collier County.