# Overseas Highway

The Overseas Highway is a 113-mile (181.9 km) highway carrying U.S. Route 1 (US 1) through the Florida Keys to Key West. Large parts of it were built on the former right-of-way of the Overseas Railroad, the Key West Extension of the Florida East Coast Railway. Completed in 1912, the Overseas Railroad was heavily damaged and partially destroyed in the 1935 Labor Day hurricane. The Florida East Coast Railway was financially unable to rebuild the destroyed sections, so the roadbed and remaining bridges were sold to the state of Florida for $640,000.
Since the 1950s, the Overseas Highway has been refurbished into a main coastal highway between the cities of Miami and Key West, offering travelers an exotic roadway through a tropical savanna environment and access to the largest area of coral reefs on the U.S. mainland. Many exotic animals such as the American alligator, American crocodile and Key deer inhabit the tropical islands of the Florida Keys.

## Route description

The Overseas Highway begins at a T intersection between US 1 and SR A1A, from which it heads east. After crossing to Stock Island and forming the boundary between the eponymous district and incorporated Key West, US 1 proceeds through unincorporated Monroe County on Boca Chica Key, past Naval Air Station Key West, and Rockland Key, where the Overseas Highway drops down to a two-lane road. It then crosses East Rockland Key, Big Coppitt Key (and its congruous district), Saddlebunch Keys, Sugarloaf Key, Park Key, Cudjoe Key (and its congruous district), Summerland Key, Ramrod Key, Middle Torch Key, Little Torch Key, Big Pine Key (and its congruous district), Scout Key, and Spanish Harbor Key. The highway expands to four lanes as it crosses the Bahia Honda Bridge, then reduces to two lanes as it traverses Bahia Honda Key, Ohio Key, Missouri Key, and Little Duck Key. After Little Duck Key, US 1 enters Knights Key, Boot Key, Key Vaca, and the town of Marathon via the Seven Mile Bridge, thus leaving the lower Keys.
US 1 runs through Marathon as a four-lane road. After Key Vaca, the road becomes two-lane once more and runs through Fat Deer Key, where it forms the northern boundary of the city of Key Colony Beach. It then continues wholly in Marathon through Long Point Key, Crawl Key, and Grassy Key. The road then crosses to Little Conch Key and then Conch Key, both part of the Duck Key district. US 1 then crosses to and traverses Long Key, which is mostly unincorporated except for the city of Layton, which the highway passes through. The road then reaches Craig Key, and then the village of Islamorada including Lower Matecumbe Key, Tea Table Key, Upper Matecumbe Key, and Windley Key. US 1 crosses a drawbridge onto Plantation Key, where it expands to four lanes and then leaves Islamorada as it crosses to Key Largo. Immediately the Overseas Highway enters Tavernier, where it temporarily splits into a pair of one-way roads through the community. Soon, the road enters the community of Key Largo, which also features another pair of one-way roads. At the northern end of the Key Largo district, about two-thirds of the way along the island, US 1 intersects County Road 905 (CR 905), which offers an alternative route out of the Keys via North Key Largo and the Card Sound Bridge. Signage approaching the intersection directs northbound motorists to take this alternative route if the lights on it are flashing. US 1 swings to the northwest, forms the southern boundary of North Key Largo, and becomes a two-lane divided road after the intersection. After crossing the Jewfish Creek Bridge (where it enters unincorporated Monroe County again) and traveling along Cross Key, US 1 crosses Manatee Creek, along with the Miami-Dade County boundary, and reaches the mainland.

### Mile markers

The Florida Department of Transportation ("FDOT") maintains mile marker signs in the Florida Keys portion of Monroe County along the Overseas Highway (U.S. Highway No. 1). Numbering commences at "0" in Key West, and increases towards the east until Islamorada where the direction changes to the northeast following the Overseas Highway to Key Largo at "106." Outside of the city of Key West and the city of Marathon, street addresses along the Overseas Highway in the Keys correspond to the mile markers. For example, the Tropical Research Laboratory of Mote Marine Laboratory has a physical address of 24244 Overseas Highway. The first two digits indicate that the Laboratory is located at Mile Marker 24 (corresponding to an address on Summerland Key). The next two digits indicate that it is about a quarter of a mile east of the Mile Marker 24 sign (MM 24.24), while the last digit, because it is an even number, indicates that it is located on the gulf side of the Overseas Highway (the term "gulf side" is used in the Middle and Lower Keys as the Overseas Highway runs east-west there; the term "bayside" is used in the Upper Keys where the Overseas Highway runs north-south. All of the Keys use the term "oceanside"):
* The first two-to-three digits denote the Mile Marker, while the next digit denotes the nearest tenth of a mile (e.g., MM 102.5).
* An address ending in an odd number indicates the location is on the Atlantic or oceanside of the Overseas Highway, while an address ending in an even number indicates the location is on the Florida Bay/Gulf of Mexico or bayside of the Overseas Highway.
Exceptions to this rule do exist, however. There are occasional addresses ending in even numbers on the oceanside and vice versa.

## History

While the Overseas Highway today runs along the former Overseas Railroad right of way, portions of the highway came into existence earlier in a different alignment while the railroad was still operating. The concept of an Overseas Highway began with the Miami Motor Club in 1921. The Florida land boom of the 1920s was underway and the club wanted to attract tourists to easily reached fishing areas, which could only be reached by boat or train at the time. The land boom also attracted real estate interests who sought vehicular access to the upper keys where there were thousands of acres of undeveloped land. The completion of the railroad further proved a highway through the keys was feasible.
Construction on the original Overseas Highway, designated State Road 4A (an extension of a route running from Miami to Homestead), lasted through most of the mid 1920s. Officially opening for traffic on January 25, 1928, the original highway existed in two segments at its greatest extent. One segment ran from the mainland via Card Sound Road to Key Largo and extended as far as Lower Matecumbe Key, while a segment in the lower keys existed from No Name Key to Key West. An automobile ferry service connected the 41-mile gap between Lower Matecumbe and No Name Keys. State Road 4A mostly ran alongside of the Overseas Railroad in the upper keys but in the lower keys, it followed a much different path than the railroad and current highway. The ferry landing on No Name Key was located at the end of what is now Watson Boulevard, which carried State Road 4A across No Name Key and Big Pine Key before it crossed to Little Torch Key. On Little Torch Key, it turned south and rejoined the railroad. It would continue along the north side of the railroad to Upper Sugarloaf Key, where it turned south and ran along the southern shoreline of Lower Sugarloaf Key, the Saddlebunch Keys, Geiger Key, and Boca Chica Key. On Boca Chica Key, it followed the shoreline south of Naval Air Station Key West's airstrip to Boca Chica Beach before crossing to Stock Island. On Stock Island, it followed Maloney Avenue and MacDonald Avenue where it rejoined the Overseas Railroad heading into Key West. Most of the State Road 4A bridges in the Lower Keys were of wooden construction and had been in use since the early 1920s.
By the early 1930s, it was clear that the ferries were insufficient for the travel needs of the keys, and Monroe County and the State Road Department began making plans to connect the two portions of State Road 4A to make a continuous highway. In 1931, a 12 mile road was built just north of the Overseas Railroad through the community of Marathon. This road was known as Key Vaca Road and ferry terminals were built at each end at Grassy Key and Hog Key. The completion of Key Vaca Road allowed the ferry route to be split into two shorter routes. The drive from Key West to the mainland was reduced by an hour after the addition of Key Vaca Road. In 1933, the state legislature created the Overseas Road and Toll Bridge District to seek federal funding to extend and connect the roadways, though funding was scarce as the country was in the midst of the Great Depression. Funding would eventually come through the Federal Emergency Relief Administration, a program established by President Franklin D. Roosevelt's New Deal. Hundreds of disgruntled World War I veterans seeking early payment of wartime pensions were employed for construction on the roadway and bridges as part of a government relief program.
Construction on a bridge connecting Lower Matecumbe Key with Long Key was already underway when the Category 5 Labor Day Hurricane struck Islamorada on September 2, 1935. The hurricane caused widespread damage throughout the area and destroyed much of the Overseas Railroad in the upper keys. Of the over 400 fatalities from the hurricane, more than half were veterans and their families. Their deaths caused anger and charges of mismanagement that led to a Congressional investigation. Just west of Lower Matecumbe Key at Mile Marker 73 on the current highway, eight concrete bridge piers and a small dredged island are all that remains of the veterans' work. The dredged island is now known as Veteran's Key and the piers remain as a tribute to the veterans with a memorial plaque on Craig Key.
After the hurricane, the Florida East Coast Railway was financially unable to rebuild the damaged sections of the Overseas Railroad. Seizing a rare opportunity, the state purchased the railroad's entire right of way south of Florida City and its remaining infrastructure for a price of $640,000. After the purchase of the railroad right of way, the Overseas Road and Toll Bridge District abandoned its original highway plans and made new plans to build the highway on the old rail bed from Lower Matecumbe Key to Big Pine Key. This would effectively connect the two segments of State Road 4A, with present-day Key Deer Boulevard connecting the new highway on Big Pine Key to the original highway on the lower keys. The railroad's bridges, which withstood the hurricane and were in good condition, were retrofitted with new two-lane wide concrete surfaces for automobile use. In the case of the Bahia Honda Rail Bridge, which was a truss bridge, the concrete road surface was built on top of the trusses. The conversion of the railroad bridges to automobile use was accomplished by Cleary Brothers Construction Co. of West Palm Beach. The full highway from the mainland to Key West was officially opened for traffic on March 29, 1938 and upon completion, the route became the southernmost segment of U.S. Route 1, which previously terminated in Miami (State Road 4A would remain as a hidden designation until the 1945 Florida State Road renumbering, when the hidden designation became State Road 5). President Franklin D. Roosevelt toured the road in 1939.
Portions of the road were tolled until April 15, 1954; toll booths were located on Big Pine Key and Lower Matecumbe Key. Pigeon Key, roughly the midway point of the Seven Mile Bridge, served as the headquarters for the "Overseas Road and Toll District." The toll for automobiles was $1, plus 25 cents per passenger.
When completed in 1938, the Overseas Highway only ran along the old railroad route in the middle keys; the original highway segments were still in use in the upper and lower keys. As the United States entered into World War II, the U.S. Navy sought improvements to the highway to improve their access from the Naval Air Station on Boca Chica Key to the mainland for national security purposes. The 1920s-era lower keys segment was less than ideal with its winding road and rickety wooden bridges. This resulted in completing the rest of the highway throughout the keys on the former railroad right of way, which the state owned and was a more direct route with smoother curves that would allow for higher speeds. Also included in this project was the construction of the highway from Florida City to Key Largo on the old railroad route via Jewfish Creek. The new alignments would shorten the route from Key West to the mainland by 17 miles. The new alignments were officially completed on May 16, 1944, with Florida Governor Spessard Holland presiding over ribbon-cutting ceremonies.
After the completion of the realignments in 1944, the original Card Sound Bridge was closed to traffic and its remains were subsequently destroyed by a fire (the Card Sound route would be restored as a secondary route in 1969 with the opening of the current bridge). Today, some segments of the original highway remain as frontage roads for the current highway. In 1946, the State Road Department began removing some of the original highway's wooden bridges that paralleled the rebuilt highway. In the lower keys where the original road ran further south, many of the wooden bridges were left in service allowing some segments of the road to become side roads. However, the original bridges that connected Stock Island and Boca Chica Key, and Geiger Key to the Saddlebunch Keys were removed. Portions of the original highway are now Boca Chica Road and Geiger Road on Boca Chica and Geiger Keys. County Road 939A runs along the original road on the Saddlebunch Keys and Sugarloaf Key, though some portions of the road are now hiking trails. Remnants of the wooden bridge at Tarpon Creek on Upper Sugarloaf Key still remain, which was destroyed by a fire in later years.
The original highway through Key Largo and Tavernier would once again become part of the Overseas Highway in the early 1970s when it was expanded to a four-lane divided highway. Here, the northbound lanes run along the route of the original highway and the southbound lanes along the route of the railroad, which is especially evident in area where the route splits into two one-way streets. The widening was the beginning of a much larger project to rebuild much of the Overseas Highway, which included replacing the aging repurposed railroad bridges with more modern bridges; some of which are able to accommodate more than two lanes of traffic. This included the Seven Mile Bridge, the Bahia Honda Bridge and the Long Key Bridge (although these three original bridges are no longer open to vehicular traffic, they became listed on the National Register of Historic Places in 1979 and are currently used for fishing and pedestrian traffic). The more modern bridges were completed in the early 1980s.
In recent years, Pigeon Key was used by the University of Miami as an oceanography laboratory, but current efforts to restore the buildings on the island have resulted in the establishment of a railroad museum there. The newer Seven Mile Bridge does not have direct access to Pigeon Key; people going there must bike or walk on 2.2 miles (3.5 km) of the Old Seven Mile Bridge from its eastern end on Knight's Key, take a shuttle bus, or take a boat to reach the island.

## Trail

In 2001, the Monroe County Commission, the Florida Department of Environmental Protection's Office of Greenways and Trails, and FDOT entered into a Memorandum of understanding to create the Florida Keys Overseas Heritage Trail (FKOHT). The trail will be a multi-use bicycle and pedestrian facility that will traverse the Florida Keys from Key Largo to Key West. Upon completion, the FKOHT will include an integrated system of educational kiosks, roadside picnic areas, scenic overlooks, fishing piers, water access points, and bicycle and jogging paths. The development of the trail will provide a mechanism for the preservation and use of the historic Flagler Railroad Bridges, 23 of which still exist and are mostly intact. Several alternatives exist for trail alignment, including cutting down the 22-foot-wide (6.7 m), 1940s-era roadway to its original 12-foot (3.7 m) spandrel width, or using the 22-foot-wide (6.7 m) roadway as is, particularly in multi-use areas. In all cases, original bridgework will be repaired or rebuilt, and the breaks created during the 1980s and 1990s fishing pier conversion will be reconnected. Where the original roadway no longer exists, the trail will be temporarily cantilevered on the side of the current US 1 highway bridge, until new 12-foot-wide (3.7 m) trail bridge sections can be built. The new sections will be built to match the historical character of the original bridges.

## In popular culture

One of animated television's Wacky Races was The Overseas Hi-Way Race, which first aired on December 28, 1968, on CBS, covering the entire actual route from Key Largo to Key West. While Long Key was correctly portrayed, most of the other in-between keys were given fictional names, and Sombrero Key was actually five miles south of the highway in open water, according to the Florida Keys–East map.
The Overseas Highway is depicted in a screenprint by American artist Ralston Crawford.
Superboy features the bridge in the season 1 opening credits. Actor John Haymes Newton is shown flying around the bridge.
An action scene involving a car and fighter jet was filmed on a portion of the old Seven Mile Bridge for the 1994 James Cameron film True Lies. No part of the bridge was destroyed during filming; an 80-foot model of the bridge built off Sugarloaf Key was blown up instead.

## Major intersections

Mileposts are taken from US 1, which begins approximately 4 miles (6.4 km) south at an intersection with Whitehead and Fleming streets in Key West.The entire route is in Monroe County.
| Location | mi | km | Destinations | Notes |
| Key West | 3.927 | 6.320 | US 1 south (North Roosevelt Boulevard) / SR A1A south (South Roosevelt Boulevard) – Business District, Airport, Beaches | US 1 continues south |
| Key West | 4.100– 4.169 | 6.598– 6.709 | Bridge over Cow Key Channel trail on sidewalk to north | Bridge over Cow Key Channel trail on sidewalk to north |
| Stock Island | 4.586 | 7.380 | MacDonald Drive | Former SR 4A |
| ​ | 5.291 | 8.515 | Key Haven Boulevard | To Raccoon Key |
| ​ | 5.997– 6.498 | 9.651– 10.458 | Bridge over Boca Chica Channel | Bridge over Boca Chica Channel |
| Boca Chica Key | 8.08 | 13.00 | Naval Air Station Key West | Interchange |
| Rockland Key | 8.790 | 14.146 | Toppino Industrial Drive | |
| East Rockland Key | 9.183 | 14.779 | Rockland Drive – NAS Truck Entrance | Former US 1 south |
| ​ | 9.508– 9.754 | 15.302– 15.698 | Bridge over Rockland Channel (trail on old bridge to south) | Bridge over Rockland Channel (trail on old bridge to south) |
| Big Coppitt Key | 10.691 | 17.205 | CR 941 south / Boca Chica Road | Northern terminus of CR 941 (former SR 941) |
| ​ | 11.181 | 17.994 | Shark Key | |
| ​ | 11.309– 11.701 | 18.200– 18.831 | Bridge over Shark Channel (trail on old bridge to the south) | Bridge over Shark Channel (trail on old bridge to the south) |
| Saddle Bunch Keys | 12.547– 12.712 | 20.192– 20.458 | Bridge over Saddle Bunch No. 5 (trail on old bridge to the south) | Bridge over Saddle Bunch No. 5 (trail on old bridge to the south) |
| Saddle Bunch Keys | 13.018– 13.185 | 20.950– 21.219 | Bridge over Saddle Bunch No. 4 (trail on old bridge to the south) | Bridge over Saddle Bunch No. 4 (trail on old bridge to the south) |
| Saddle Bunch Keys | 14.118– 14.259 | 22.721– 22.948 | Bridge over Saddle Bunch No. 3 (trail on old bridge to the south) | Bridge over Saddle Bunch No. 3 (trail on old bridge to the south) |
| Saddle Bunch Keys | 14.328 | 23.059 | Blue Water Drive | |
| Saddle Bunch Keys | 14.496– 14.616 | 23.329– 23.522 | Bridge over Saddle Bunch No. 2 (trail on old bridge to the south) | Bridge over Saddle Bunch No. 2 (trail on old bridge to the south) |
| Saddle Bunch Keys | 14.968 | 24.089 | East Circle Drive | |
| Saddle Bunch Keys | 15.261– 15.504 | 24.560– 24.951 | Bridge over Lower Sugarloaf Channel (trail on old bridge to the south) | Bridge over Lower Sugarloaf Channel (trail on old bridge to the south) |
| ​ | 16.370– 16.455 | 26.345– 26.482 | Bridge over Harris Channel | Bridge over Harris Channel |
| Lower Sugarloaf Key | 16.955 | 27.286 | CR 939 south / Sugarloaf Boulevard | Northern terminus of CR 939 (former SR 939) |
| ​ | 17.451– 17.472 | 28.085– 28.118 | Bridge over Harris Gap Channel | Bridge over Harris Gap Channel |
| ​ | 17.658– 17.741 | 28.418– 28.551 | Bridge over North Harris Channel | Bridge over North Harris Channel |
| ​ | 18.600– 18.755 | 29.934– 30.183 | Bridge over Park Channel (trail on old bridge to the south) | Bridge over Park Channel (trail on old bridge to the south) |
| Sugarloaf Key | 19.349 | 31.139 | Crane Boulevard | |
| Sugarloaf Key | 19.970 | 32.139 | CR 939B south | Old SR 4A; northern terminus of CR 939 (former SR 939) |
| ​ | 20.150– 20.433 | 32.428– 32.884 | Bridge over Bow Channel (trail on old bridge to the south) | Bridge over Bow Channel (trail on old bridge to the south) |
| Cudjoe Key | 21.409 | 34.454 | Blimp Road | |
| ​ | 23.471– 23.682 | 37.773– 38.112 | Bridge over Kemp's Channel (partial old bridge to the south) | Bridge over Kemp's Channel (partial old bridge to the south) |
| Summerland Key | 25.197 | 40.551 | CR 942 south / East Shore Drive | |
| ​ | 25.413– 26.278 | 40.898– 42.290 | Bridge over Nile's Channel (partial old bridge to the south) | Bridge over Nile's Channel (partial old bridge to the south) |
| Ramrod Key | 27.264 | 43.877 | Indies Road | |
| ​ | 27.504– 27.629 | 44.263– 44.465 | Bridge over Torch Ramrod Channel | Bridge over Torch Ramrod Channel |
| Middle Torch Key | 27.836 | 44.798 | Middle Torch Road – Big Torch Key | |
| ​ | 27.895– 28.052 | 44.893– 45.145 | Bridge over Torch Key Channel | Bridge over Torch Key Channel |
| Little Torch Key | 28.216 | 45.409 | State Road 4A | Former SR 4A |
| ​ | 28.625– 28.801 | 46.067– 46.351 | Bridge over South Pine Channel (partial old bridge to the south) | Bridge over South Pine Channel (partial old bridge to the south) |
| ​ | 29.411– 29.552 | 47.332– 47.559 | Bridge over North Pine Channel | Bridge over North Pine Channel |
| Big Pine Key | 30.527 | 49.128 | CR 940 north / Key Deer Boulevard – National Key Deer Visitor Center | Southern terminus of CR 940 (former SR 940) |
| ​ | 33.130– 33.791 | 53.318– 54.381 | Bridge over Spanish Harbor Channel | Bridge over Spanish Harbor Channel |
| ​ | 35.272– 36.544 | 56.765– 58.812 | Bahia Honda Bridge over Bahia Honda Channel (partial old bridge to the south) | Bahia Honda Bridge over Bahia Honda Channel (partial old bridge to the south) |
| Bahia Honda Key | 36.794 | 59.214 | Bahia Honda State Park | |
| ​ | 38.361– 38.571 | 61.736– 62.074 | Bridge over Ohio Bahia Honda Channel (trail on old bridge to the north) | Bridge over Ohio Bahia Honda Channel (trail on old bridge to the north) |
| Ohio Key | 38.75 | 62.36 | no major intersections | |
| ​ | 38.896– 39.176 | 62.597– 63.048 | Bridge over Missouri Ohio Channel (trail on old bridge to the north) | Bridge over Missouri Ohio Channel (trail on old bridge to the north) |
| ​ | 39.448– 39.620 | 63.485– 63.762 | Bridge over Little Duck Missouri Channel (trail on old bridge to the north) | Bridge over Little Duck Missouri Channel (trail on old bridge to the north) |
| Little Duck Key | 39.823 | 64.089 | Veterans Memorial Park | |
| ​ | 40.011– 46.804 | 64.391– 75.324 | Seven Mile Bridge over Moser Channel (partial old bridge via Pigeon Key to the north) | Seven Mile Bridge over Moser Channel (partial old bridge via Pigeon Key to the north) |
| Marathon | 47.186 | 75.939 | Knights Key | |
| Marathon (Vaca Key) | 48.059 | 77.343 | CR 931 north (20th Street) | Southern terminus of CR 931 (former SR 931) |
| Marathon (Vaca Key) | 49.965 | 80.411 | CR 931 south / Sombrero Beach Road – Sombrero Beach | Northern terminus of CR 931 (former SR 931) |
| Marathon | 53.001– 53.081 | 85.297– 85.426 | Bridge over Vaca Cut trail on sidewalk to north | Bridge over Vaca Cut trail on sidewalk to north |
| Marathon (Fat Deer Key) | 53.610 | 86.277 | Sadowski Causeway – Key Colony Beach | |
| Marathon (Long Point Key) | 56.191 | 90.431 | Curry Hammock State Park | |
| Marathon (Crawl Key) | 56.459 | 90.862 | Banana Boulevard | |
| Marathon (Grassy Key) | 57.594 | 92.689 | Kyle Avenue | |
| ​ | 60.498– 60.786 | 97.362– 97.826 | Bridge over Tom's Harbor No. 4 (trail on old bridge to the south) | Bridge over Tom's Harbor No. 4 (trail on old bridge to the south) |
| Duck Key | 61.051 | 98.252 | Hawks Cay | |
| ​ | 61.418– 61.680 | 98.843– 99.264 | Bridge over Tom's Harbor Cut (trail on old bridge to the south) | Bridge over Tom's Harbor Cut (trail on old bridge to the south) |
| Conch Key | 62.846 | 101.141 | North Conch Avenue | |
| ​ | 63.140– 65.446 | 101.614– 105.325 | Long Key Bridge over Long Key Channel (trail on old bridge to the south) | Long Key Bridge over Long Key Channel (trail on old bridge to the south) |
| Long Key | 67.404 | 108.476 | Long Key State Park | |
| ​ | 70.735– 71.670 | 113.837– 115.342 | Bridge over Channel No. 5 (partial old bridge to the north) | Bridge over Channel No. 5 (partial old bridge to the north) |
| Craig Key | 72 | 116 | no major intersections | |
| Islamorada | 72.642– 73.000 | 116.906– 117.482 | Bridge over Channel No. 2 (trail on old bridge to the north) | Bridge over Channel No. 2 (trail on old bridge to the north) |
| Islamorada (Lower Matecumbe Key) | 74.403 | 119.740 | Gulfview Drive | |
| Islamorada | 77.531– 77.703 | 124.774– 125.051 | Bridge over Lignumvitae Channel | Bridge over Lignumvitae Channel |
| Islamorada | 77.966– 78.353 | 125.474– 126.097 | Bridge over Indian Key Channel | Bridge over Indian Key Channel |
| Islamorada | 79.177– 79.318 | 127.423– 127.650 | Bridge over Tea Table Channel | Bridge over Tea Table Channel |
| Islamorada | 79.708– 79.761 | 128.278– 128.363 | Bridge over Tea Table Relief | Bridge over Tea Table Relief |
| Islamorada (Upper Matecumbe Key) | 80.425 | 129.431 | Frontage Road | Former SR 4A |
| Islamorada (Upper Matecumbe Key) | 83.509 | 134.395 | Frontage Road | Former SR 4A |
| Islamorada | 83.879– 84.001 | 134.990– 135.187 | Bridge over Whale Harbor Channel | Bridge over Whale Harbor Channel |
| Islamorada | 85.578– 85.739 | 137.724– 137.984 | Snake Creek Bridge over Snake Creek | Snake Creek Bridge over Snake Creek |
| Islamorada (Plantation Key) | 90.513 | 145.667 | Plantation Avenue / Sunshine Boulevard / Bessie Road | |
| ​ | 90.895– 90.955 | 146.281– 146.378 | Bridge over Tavernier Creek Waterway | Bridge over Tavernier Creek Waterway |
| Tavernier | 91.485 | 147.231 | Ocean Boulevard | |
| Key Largo | 103.430– 103.454 | 166.454– 166.493 | Bridge over Marvin D. Adams Waterway | Bridge over Marvin D. Adams Waterway |
| Key Largo | 106.312 | 171.093 | CR 905 north (Card Sound Road) – Miami | Old SR 4A; Southern terminus of CR 905 (former SR 905) |
| Key Largo | 113.00 | 181.86 | US 1 north (Dixie Highway) | US 1 continues north to Florida City, Homestead, and Miami |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi |||||