Monroe County, Florida

Monroe County is a county in Florida, United States, spanning the Florida Keys and a slice of
mainland Everglades about 160 miles southwest of Miami. It had a population of 82,874 at the
2020 census and covers 983 square miles of land (2,550 km2), with a further 2,754 square miles
of water — nearly three-quarters of the county’s total area. The county centers near
25°7′N 81°9′W, a point that falls inside the largely uninhabited Everglades
mainland rather than on the populated island chain.

Key West is the county seat and largest city; its postal code is 33040. The county holds 5
incorporated cities, towns and villages and roughly 20 unincorporated communities strung along
the Keys, and it runs on Eastern Time. Its FIPS code is 12087.

Towns & Villages in Monroe County

Monroe County has 13 named places on record with a 2020 census count: 5 incorporated
municipalities and 8 unincorporated communities (CDPs) with no local government of their own.
CDP stands for census designated place. More than a dozen smaller CDPs and trailer communities
exist along the Overseas Highway with too little data to list reliably here.

Islamorada is officially the “Village of Islands” and governs five separate keys:
Tea Table, Lower Matecumbe, Upper Matecumbe, Windley and Plantation. Marathon Shores is not a
separate place — it is a neighborhood inside the city of Marathon, not its own CDP, despite
appearing that way on some older place lists. Stock Island shares Key West’s ZIP codes
even though it is a distinct, unincorporated CDP.

ZIP Codes

• 33040 — Key West (also covers Stock Island and Big Coppitt Key)
• 33037 — Key Largo
• 33070 — Tavernier
• 33036 — Islamorada
• 33050 — Marathon (also serves Duck Key)
• 33051 — Key Colony Beach
• 33043 — Big Pine Key
• 33042 — Cudjoe Key and Summerland Key
• 33001 — Layton

Florida drops the ZIP+4-style local post office distinction the Keys once had for individual
islands; smaller communities such as Ramrod Key and Sugarloaf Key use a neighboring CDP’s
code rather than one of their own.

Geography

Monroe County is unusual among Florida counties: 99.9 percent of its residents live on the
narrow island chain of the Florida Keys, while the mainland portion — part of Everglades
National Park — makes up 87 percent of the county’s land area and held just 17
people at the 2020 census. The Keys themselves form a roughly 120-mile arc of coral and
limestone islands running southwest from the mainland, connected end to end by the Overseas
Highway. Of the county’s 983 square miles of land, most sits within Everglades and Big
Cypress National Preserve boundaries rather than on the inhabited Keys.

Only two counties border Monroe directly, both to the north: Miami-Dade County and Collier
County. Miami-Dade County and
Collier County both share a land
boundary with Monroe across the Everglades; no county borders the inhabited Keys, which are
surrounded on both sides by the Atlantic Ocean and the Gulf of Mexico.

Demographics

Monroe County had a population of 82,874 at the 2020 census. Key West and Key Largo are by far
the two largest communities, together accounting for roughly half the county’s residents.
Population density works out to about 84 people per square mile of land countywide, but that
figure is misleading — nearly everyone lives on the narrow, developed islands, where
effective density runs far higher, while the Everglades mainland is almost empty.

Economy & Local Life

Tourism dominates the county’s economy: about 54 percent of workers in Monroe County work
in the tourism industry, and visitor spending brought the county $2.7 billion in 2016. Key West
functions as the county’s commercial hub, with a working cruise port, charter fishing fleet
and a concentration of hotels, restaurants and dive operators. Naval Air Station Key West, on
Boca Chica Key and Truman Annex, is a major year-round employer alongside the Monroe County
School District and the county government itself. The county’s biggest annual event is
Fantasy Fest, a costumed street festival held in Key West each October; the Conch Republic
Independence Celebration follows every April 23, commemorating Key West’s 1982 mock
secession from the United States.

History

Monroe County was created on 3 July 1823, named for James Monroe, the fifth president of the
United States. Key West grew quickly after the United States acquired Florida in 1821; by the
1830s it was the wealthiest city per capita in the country, built on maritime salvage and
wrecking along the reef-lined shipping lanes offshore.

Standard Oil co-founder Henry Flagler built the Overseas Railroad down the island chain,
riding the first train into Key West aboard his private railcar in 1912. The Labor Day
Hurricane of 1935, a Category 5 storm, killed more than 400 people and washed out over 40 miles
of track, bankrupting the line. Florida highway authorities rebuilt much of the route as the
Overseas Highway, now US 1, using the surviving railroad bridges and embankments.

Getting There

US 1 — the Overseas Highway — is the county’s only road link to the mainland
and runs its entire length; SR A1A and CR 905 serve Key Largo and North Key Largo. No interstate
reaches Monroe County.

• Miami — about 160 miles northeast via US 1
• Homestead — about 100 miles northeast, the nearest mainland city
• Naples — roughly 130 miles north across the Everglades
• Fort Lauderdale — about 190 miles northeast

Key West International Airport, at the county seat’s eastern end, is the county’s
main commercial airport; Florida Keys Marathon International Airport offers additional flights
from Marathon. Miami International Airport, about 160 miles up US 1, is the nearest large hub.
No Amtrak service reaches the Keys; the closest station is in Miami.

Frequently Asked Questions

Where is Monroe County located?
It covers the Florida Keys and a mainland Everglades strip in the far south of Florida, about
160 miles southwest of Miami, bordered by Miami-Dade and Collier counties.

What is the population of Monroe County?
82,874 at the 2020 census, with Key West and Key Largo holding roughly half that total.

How big is Monroe County?
983 square miles of land (2,550 km2), plus 2,754 square miles of water — the county is
nearly three-quarters water.

What is the county seat of Monroe County?
Key West is the county seat and largest city.

How many towns and cities are in Monroe County?
Five incorporated places — Key West, Marathon, Islamorada, Key Colony Beach and Layton
— plus around 20 unincorporated communities along the Keys, including Key Largo, Stock
Island, Big Pine Key and Tavernier.

What ZIP codes does Monroe County use?
33040 for Key West, 33037 for Key Largo, 33070 for Tavernier, 33036 for Islamorada, 33050 for
Marathon, 33051 for Key Colony Beach, 33043 for Big Pine Key, 33042 for Cudjoe and Summerland
Key, and 33001 for Layton.

What is Monroe County known for?
The Florida Keys and the Overseas Highway, Ernest Hemingway’s former home in Key West,
and Fantasy Fest, its costumed October street festival.

More counties in this state: Towns and villages in Florida.