The Florida Keys is an archipelago of about 1700 islands in the southeast US. They start 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 90 miles (145 km) from Cuba. The Florida Keys are between about 23.5 and 25.5 degrees North latitude, in the subtropics. 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.
U.S. Highway 1 leads from Miami leads to the Keys via the famous Overseas Highway.
The two main airports in the Keys are the seaplane base on Marathon Key (ICAO: 42FL) and Key West International Airport  (ICAO: KEYW). These are only used by private or commuter aircraft, mainly coming in from Miami (ICAO: KMIA IATA: MIA), which is the closest international airport.
Greyhound has service to and from the Florida Keys. There are terminals on Marathon, Big Pine Key, and Key West.
Multiple ferry services are available from Fort Myers to Key West. Most of them are large catamarans that will accommodate 20-30 passengers. Sailing time is about 3 hours.
The Keys (at least the accessible, commercial islands) are connected by US Highway 1. A useful and interesting "quirk" about the linearity of the Keys (and US-1) is that directions to establishments and attractions are locally described by the "Mile Markers" along US-1. If you ask someone how to get to a certain beach or hotel, they will tell you that it is at "Mile Marker 68.5"; many signs and brochures will say "MM 68.5" (of course, there is no mile marker 68.5, this just means that the hotel is halfway between mile markers 68 and 69). These numbers start at zero at the start of US-1 on Key West, so the numbers get larger as you go north.
The speed limits in the Keys are generally 45 MPH on the built-up Islands, and 55 MPH on the bridges and less built-up islands. There are areas (very built-up strips, or animal sanctuaries) where the speed drops to 35 MPH.
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.
Keys in Biscayne National Park (accessible only by boat) in Miami-Dade County
Boca Chita Key
True Florida keys, exposed ancient coral reefs
Old Rhodes Key
Keys in Monroe County
Upper Matecumbe Key
Lower Matecumbe Key
(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.)
Long Key (formerly known as Rattlesnake Key)
Long Point Key
Fat Deer Key
(Key Vaca, Boot Key, Fat Deer Key, Long Point Key, Crawl Key and Grassy Key are incorporated in the city of Marathon)
Little Duck Key
Ohio Key (also known as Sunshine Key)
Bahia Honda Key
Spanish Harbor Keys
West Summerland Key
No Name Key
Big Pine Key
Little Torch Key
Middle Torch Key
Big Torch Key
Lower Sugarloaf Key
Big Coppitt Key
East Rockland Key
Boca Chica Key
Key Haven (Raccoon Key)
These are accessible by boat.
the Marquesas Keys
the Dry Tortugas (not shown on map)