It’s certainly a unique experience to travel to islands by car. The Florida Keys Overseas Highway is a marvel of engineering that transformed these erstwhile remote isles into world renowned destinations for adventure travelers.

Bahia Honda Bridge

The old Bahia Honda steel trestle was converted to a concrete bridge for cars. Portions of the road were tolled until 1954; toll booths were located on Big Pine Key and Lower Matecumbe.

Of course it started with Henry Flager’s ambition to extend his rail network to a deep water port that could serve the newest wonder of the modern world — the Panama Canal. Henry knew that ships carrying cargo from afar would dock at the nearest rail station to unload untold quantities of goods and treasures destined for the American mainland.

Completed in 1912, the Overseas Railroad was heavily damaged and partially destroyed in the Labor Day Hurricane of 1935. 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. 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 operational.

State Road 4A

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.

The 18 Mile Stretch

The construction of the highway from Florida City to Key Largo via Jewfish Creek (known as the 18-Mile Stretch) was officially completed on May 16, 1944, shortened the route to the mainland by 17 miles.

Modern Improvements

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 re-purposed 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.

The Mile Markers

The famous mile markers, starting in Key West, provide not only a measure of distance and location, but are the basis for most of the addresses along the route. An address ending in an even digit denotes the Atlantic Ocean side while an odd digit denotes an address on the Florida Bay/Gulf of Mexico side.