Monroe County Florida map | Key Largo to Key West

Monroe County Florida map — Monroe County includes the inhabited Florida Keys from Key Largo through Islamorada, Marathon, Big Pine Key, and Key West, as well as an extensive mainland section of the Everglades across Florida Bay. The island corridor is long and narrow, while much of the county’s land area consists of roadless wetlands.

This guide separates the Upper, Middle, and Lower Keys; explains U.S. 1 mile markers and the Seven Mile Bridge; and places mainland Flamingo and remote Dry Tortugas outside the continuous island road corridor. Because bridges and a single highway govern most overland travel, straight-line distance is often a poor measure of actual access.

Monroe County Florida map showing Key West, Marathon, Key Largo — Monroe County map centered on Key West and Marathon

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Map file: County reference map
File format: ZIP

Download the Monroe County map

Table of Contents

Quick Facts

State: Florida
County: Monroe County
County seat: Key West
FIPS code: 12087
Land area: 983.04 square miles (2020 U.S. Census basis)
Incorporated municipalities: Key West, Marathon, Key Colony Beach, Layton, and Islamorada
Major unincorporated communities: Key Largo, Tavernier, Big Pine Key, Cudjoe Key, and Stock Island
Surrounding waters: Florida Bay, Atlantic Ocean, Straits of Florida, and Gulf of Mexico
Primary roads: SR 5/U.S. 1 Overseas Highway and CR 905/Card Sound Road
Major protected areas: Everglades National Park, Dry Tortugas National Park, and Florida Keys National Marine Sanctuary

What the Map Shows

The Upper Keys begin at Key Largo and continue through Tavernier and Islamorada’s Plantation, Windley, Upper Matecumbe, and Lower Matecumbe keys. Key Largo is an unincorporated community, whereas Islamorada is an incorporated village spanning several islands. Island names, community names, and municipal boundaries therefore should not be treated as identical layers.

The Middle Keys include Layton on Long Key, Grassy Key, Duck Key, and Marathon centered on Vaca Key. Key Colony Beach is a separate city on Shelter Key beside Marathon. Southwest of Marathon, the Seven Mile Bridge enters the Lower Keys, followed by Big Pine Key, Cudjoe Key, Sugarloaf Key, Stock Island, and finally the county seat at Key West.

Across Florida Bay, the mainland county contains Cape Sable, Flamingo, and broad Everglades wetlands and mangrove waterways. Flamingo is not one of the Florida Keys; it is a mainland park location on Florida Bay. About 70 miles west of Key West, the seven small islands of Dry Tortugas National Park are reachable only by boat or seaplane.

County Layout and Location

Monroe County has an unusual geography that combines the southwestern Florida mainland, most of the Florida Keys, and distant offshore islands. Its mainland section borders Miami-Dade and Collier counties, but its population centers are across Florida Bay on the Keys. Florida Bay and Gulf waters lie north and northwest of the chain; the Atlantic and Straits of Florida lie south and southeast.

The Keys are low limestone and coral islands separated by channels. U.S. 1 and dozens of bridges create a linear land route, but there is little possibility of detouring parallel to it. The Seven Mile Bridge spans the corridor between Knights Key at Marathon and Little Duck Key in the Lower Keys; FDOT’s project study covers roughly 7.5 miles, and the crossing marks a major transition from the Middle to Lower Keys.

Most of the mainland section belongs to the Everglades wetland and mangrove system and has no road connection directly across Florida Bay to the Keys. Driving from the Keys to Flamingo requires returning north on U.S. 1 toward Florida City and Homestead, then entering Everglades National Park by its mainland road. Locations that appear close across the bay can therefore be hours apart by road.

Local Context

SR 5/U.S. 1 is known in the Keys as the Overseas Highway and connects homes, businesses, islands, and bridges from Key Largo to Key West. Mile markers begin at zero in Key West and increase northeastward: the Lower Keys are roughly MM 4–40, Marathon MM 40–63, Islamorada MM 63–90, and Key Largo MM 90–108. Locals use these numbers as a practical location and address system.

At the northern end, U.S. 1 continues directly toward Florida City, while CR 905 and Card Sound Road provide an additional mainland connection for northern Key Largo and Ocean Reef. That route does not become a parallel highway through the Middle and Lower Keys. A bridge closure, crash, construction zone, or phased evacuation can therefore affect travel far beyond the immediate island.

Services also follow this sequence. Key Largo and Islamorada anchor the Upper Keys near the mainland; Marathon supplies hospital, airport, marine, and commercial functions in the Middle Keys; Big Pine Key and nearby islands form the Lower Keys residential district; and Stock Island and Key West concentrate government, port, and airport activity at the southwestern end. Dry Tortugas and the mainland park lands remain outside this continuous road-based service corridor.

Ways to Use This Map

Trace Key Largo, Islamorada, Marathon, Big Pine Key, and Key West from northeast to southwest
Use mile-marker ranges to distinguish the Upper, Middle, and Lower Keys
Locate the Seven Mile, Long Key, and Bahia Honda bridge crossings
Compare the U.S. 1 and Card Sound Road approaches from the mainland
Separate mainland Flamingo and Cape Sable from the inhabited island corridor
Recognize why no highway continues from Key West to Dry Tortugas

Frequently Asked Questions

How many through roads reach Key West?

U.S. 1, the Overseas Highway, is the single continuous through-road from Key Largo to Key West. Card Sound Road is an additional mainland approach at the Upper Keys, but it does not run parallel through the Middle and Lower Keys. Bridge conditions and evacuation phases therefore have countywide importance.

Can you drive directly from the Florida Keys to Flamingo?

No road crosses Florida Bay. Drivers must travel north on U.S. 1 toward Florida City and Homestead, then use the main entrance and park road through Everglades National Park to reach Flamingo.

Which direction do the mile-marker numbers increase?

They begin at mile marker zero in Key West and increase toward the northeast and the mainland. Marathon is generally around MM 40–63, Islamorada MM 63–90, and Key Largo MM 90–108, so an address marker gives a quick estimate of position along the island chain.

Sources

Green Map creates custom-edited map images using open geographic data sources such as geoBoundaries, Natural Earth, OpenStreetMap, and government open data.

These maps are edited visual materials, not raw data files, and are provided for education, documents, presentations, and graphic reference.