The Florida Keys is an archipelago of about 1700 islands in the southeast United States. They begin at the southeastern tip of the Florida peninsula, about 15 miles south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry Tortugas. The islands lie along the Florida Straits, dividing the Atlantic Ocean to the east from the Gulf of Mexico to the west, and defining one edge of Florida Bay. At the nearest point, the southern tip of Key West is just 98 miles (157 km) from Cuba. The Florida Keys are between about 23.5 and 25.5 degrees North latitude, in the subtropics. The climate of the Keys however, is defined as tropical according to Köppen climate classification. More than 95 percent of the land area lies in Monroe County, but a small portion extends northeast into Miami-Dade County, primarily in the city of Islandia, Florida. The total land area is 355.6 km² (137.3 sq mi). As of the 2000 census the population was 79,535, with an average density of 223.66/km² (579.27/sq mi), although much of the population is concentrated in a few areas of much higher density, such as the city of Key West, which has 32% of the entire population of the Keys.
The city of Key West is the county seat of Monroe County, which consists of a section on the mainland which is almost entirely in Everglades National Park, and the Keys islands from Key Largo to the Dry Tortugas.

Origins
U.S. Highway 1, the "Overseas Highway" runs over most of the inhabited islands of the Florida Keys. The islands are listed in order from north and east to south and west.

Major islands
Keys in Biscayne National Park (accessible only by boat) in Miami-Dade County
Keys in Monroe County
(Plantation Key through Lower Matecumbe Key are incorporated as Islamorada, Village of Islands. The "towns" of Key Largo, North Key Largo and Tavernier, all on the island of Key Largo, are not incorporated.)

Transitional keys

• Soldier Key
  Ragged Keys
  Boca Chita Key
  Sands Key
  True Florida keys, exposed ancient coral reefs
  
  
  
  • Elliott Key
    Adams Key
    Reid Key
    Rubicon Keys
    Totten Key
    Old Rhodes Key
    Key Largo
    Plantation Key
    Windley Key
    Upper Matecumbe Key
    Lignumvitae Key
    Lower Matecumbe Key Upper keys
    (Key Vaca, Boot Key, Fat Deer Key, Long Point Key, Crawl Key and Grassy Key are incorporated in the city of Marathon)
    
    Craig Key
    Fiesta Key
    Long Key (formerly known as Rattlesnake Key)
    Conch Key
    Duck Key
    Grassy Key
    Crawl Key
    Long Point Key
    Fat Deer Key
    Key Vaca
    Boot Key
    Knight's Key
    Pigeon Key Lower keys
    These are accessible by boat.
    among others
    
    Sunset Key
    Wisteria Island
    the Marquesas Keys
    the Dry Tortugas (not shown on map) Outlying islands
    Most islands are connected by the Overseas Highway. There has been a railway, but in 1935 its operation was discontinued. See also the history section.
    
    Transportation
    
    History
    The Keys were long accessible only by water. This changed with the completion of Henry Flagler's Overseas Railway in the early 1910s. Flagler, a major developer of Florida's Atlantic coast, extended his Florida East Coast Railway down to Key West with an ambitious series of over-sea railroad trestles.
    
    Overseas Railway
    Main article: Labor Day Hurricane of 1935
    One of the worst hurricanes to strike the U.S. made landfall near Islamorada in the Upper Keys on Labor Day, Monday Sept. 2. Winds were estimated to have gusted to 200 mph, raising a storm surge more than 17.5 feet above sea level that washed over the islands. More than 400 people were killed, though some estimates place the number of deaths at more than 600.
    The Labor Day Hurricane is one of only three hurricanes to make landfall at Category 5 strength on the U.S. coast since reliable weather records began (about 1850). The other storms were Camille (1969) and Andrew (1992).
    In 1935, new bridges were under construction to connect a highway through the entire Keys. Hundreds of World War I veterans working on the roadway as part of a government relief program were housed in unreinforced buildings in three construction camps in the Upper Keys. When the evacuation train failed to reach the camps before the storm, more than 200 veterans perished. Their deaths caused anger and charges of mismanagement that led to a congressional investigation.
    The storm also ended the 23-year run of the Overseas Railway; the damaged tracks were never rebuilt, and the Overseas Highway (U.S. Highway 1) replaced the railroad as the main transportation route from Miami to Key West.
    
    Labor Day Hurricane of 1935
    One of the longest bridges when it was built, the Seven Mile Bridge connects Knight's Key (where the city of Marathon is located in the Middle Keys) to Little Duck Key in the Lower Keys. Almost true to its name, the piling-supported concrete bridge is 35,862 ft or 6.79 miles (10.93 km) long. The current bridge bypasses Pigeon Key, a small island that an older bridge crossed (a section of the old bridge remains for access to the island).
    After the destruction of the Keys railway by the Labor Day Hurricane of 1935, the railroad bridges, including the Seven Mile Bridge, were converted to automobile roadways. U.S. Route 1 runs the length of the Keys and up the East Coast to Maine; the Keys section is also called the Overseas Highway.
    
    Seven Mile Bridge
    
    
    Main article: Conch Republic Conch Republic
    The Keys are in the subtropics between 24 and 25 degrees north latitude. The climate and environment are closer to that of the Caribbean than the rest of Florida, though unlike the Caribbean's volcanic islands, the Keys were built by plants and animals.
    The Upper Keys islands are remnants of large coral reefs, which became fossilized and exposed as sea level declined. The Lower Keys are composed of sandy-type accumulations of limestone grains produced by plants and marine organisms.
    The natural habitats of the Keys are upland forests, inland wetlands and shoreline zones. Soil ranges from sand to marl to rich, decomposed leaf litter. In some places, "caprock" (the eroded surface of coral formations) covers the ground. Rain falling through leaf debris becomes acidic and dissolves holes in the limestone, where soil accumulates and tree roots find purchase.
    The climate is considered to be tropical wet-and-dry (Koppen climate classification Aw), and the Keys are the only frost-free place in Florida. There are two main "seasons": hot, wet, and humid from about June through October, and somewhat drier and cooler weather from November through May. Many plants grow slowly or go dormant in the dry season. Some native trees are deciduous, and drop their leaves in the winter or with spring winds.
    The Keys have distinctive plant and animals species, some found nowhere else in America, as the Keys define the northern extent of their ranges. The climate also allows many imported plants to thrive. Nearly any houseplant known to commerce, and most landscape plants of the South, can thrive in the Keys climate. Some exotic species which arrived as landscape plants now invade and threaten natural areas.
    Some plants that seem to define the Keys are not native, including coconut palm, bougainvillea, hibiscus, and papaya.
    The well-known and very sour Key lime (or Mexican lime) is a naturalized species, apparently introduced from the Yucatán Peninsula of Mexico, where it had previously been introduced from Malaysia by explorers from Spain. The tree grows vigorously and has thorns, and produces golf-ball-size yellow fruit which is particularly acidic (even in highly alkaline coral sand soil) and uniquely fragrant. Naturally, Key lime pie was invented here as well.
    The Keys are also home to unique animal species, including the Key deer, protected by the National Key Deer Refuge, and the American crocodile. About 70 miles (110 km) west of Key West is Dry Tortugas National Park, one of the most isolated and therefore well-preserved in the world. The name derives from the fact that when Spanish explorers arrived no fresh water could be found, and the small hump-shaped islands look like tortoise (tortuga in Spanish) shells from a distance.
    The waters surrounding the Keys are part of a protected area known as the Florida Keys National Marine Sanctuary.
    
    Environment
    The Keys are regularly threatened by tropical storms and hurricanes, leading to evacuations to the mainland. Untouched for many years, a carefree attitude led many residents to view "mandatory" evacuations as "voluntary" and "voluntary" evacuation orders as nothing at all. The attitude proved dangerous when Hurricane Georges ((IPA: /ʒɔʒ/)), after tearing up much of the Caribbean, caused damage and extensive flooding in the Lower Keys in 1998, before making landfall in Mississippi. In 2005, Hurricanes Katrina, Rita and Wilma affected the Keys (although none made a direct hit), causing widespread damage and flooding. The most severe hurricane to hit the area was the Labor Day Hurricane of 1935, a Category 5 hurricane.
    Tropical cyclones present special dangers and challenges to the entire Keys. Because no area of the islands is more than 20 feet above sea level (and many are only a few feet elevation), and water surrounds the islands, nearly every neighborhood is subject to devastating flooding as well as hurricane winds. In response, many homes in the Keys are built on concrete stilts with the first floor being not legally habitable and enclosed by breakaway walls that are not strongly attached to the rest of the house. Nonetheless, Monroe county, as reported in the Federal Register, has estimated that there are between 8,000 and 12,000 illegal enclosures inhabited by people .
    Because of the threat from storm surge, evacuations are routinely ordered when the National Weather Service issues a hurricane watch or warning, and are sometimes ordered for a tropical storm warning. Evacuation of the Keys depends on causeways and the two-lane highway to the mainland. Time estimates for evacuating the entire Keys range from 12 to 24 hours. Evacuation estimates are significant in emergency planning, of course, but also because they are a factor in local and state regulations for controlling development. The building permit allocation was increased in 2005 when local governments reduced estimates for evacuation.
    In the active hurricane seasons of 2004 and 2005, the Keys were under mandatory evacuation orders several times. In August, 2004, Hurricane Charley passed about 70 miles west of Key West, bringing tropical storm winds to the lower keys. The lower keys were evacuated in preparation for Hurricane Ivan in September, 2004 and Hurricane Dennis in July, 2005, but neither hurricane came close enough to the Keys to do much damage. Hurricane Katrina, which went on to devastate parts of Louisiana and Mississippi, moved through south Florida in August, 2005 and tracked southwest past Key West, causing minor damage and flooding. Hurricane Rita, which went on to destroy parts of Louisiana and Texas, grew from a tropical storm to a Category 2 hurricane as it moved westward from the Bahamas, passing south of Key West and causing damage and surge flooding as far north as Key Largo. In October, 2005, Hurricane Wilma became the most devastating hurricane to hit the Keys in decades when it passed just northwest of Key West. The city was left under 3 to 6 feet (1 to 2 metres) of water from the storm surge, and major flooding was reported throughout the Keys up to Key Largo.
    
    Culture and recreation