Old Seven Mile Bridge

Old Seven Mile Bridge is the restored public section of Henry Flagler’s original Overseas Railroad crossing, now a 2.2-mile route over open water from Marathon to Pigeon Key. The bridge itself is the draw: old piers and steelwork, wide water views, and the newer highway bridge running nearby. If you want to experience the crossing, make time to get out here; it’s much more than a quick roadside look.

Pigeon Key is 2.2 miles from the Marathon landing, so walking there and back is 4.4 miles. The paved span is for walking and cycling, and the Pigeon Key Express tram is another way to reach the island. Check its current service and return arrangements before you rely on it. Walking the bridge is free; entering Pigeon Key and its museum requires separate paid admission.

The landing is beside Overseas Highway just past Knights Key Boulevard. Its small lot holds up to 35 vehicles, so parking is limited. The route is fully exposed to sun and wind, with little shade; bring water and plan for the heat. No bridge-side food or water stop or public restroom is confirmed, so don’t count on facilities along the walk.

Pigeon Key is a small island at the far end of the restored span. Its museum occupies the former assistant bridge tender’s house, and other historic buildings have been restored for exhibits, classrooms, and bunkhouses. The island visit gives the walk a second purpose: you can see the place that supported the people who built and worked on this crossing.

The original Knights Key Bridge was built for Henry Flagler’s Florida East Coast Railway extension to Key West, completed in 1912. At the height of construction, about 400 workers lived on Pigeon Key. After the 1935 Labor Day hurricane ended the railroad, the Overseas Highway took over the route in 1938. The modern Seven Mile Bridge opened in 1982 and bypassed the old crossing; it’s the newer road bridge you see alongside the historic one.

The old bridge closed for restoration in 2016 and reopened as a public walking and cycling route in January 2022. Crews replaced thousands of corroded plates and rivets and the original 1936 I-beams, added aluminum railings, and returned the structure to its Federal Blue finish. The restored 2.2-mile section is open to visitors even though the broader historic bridge line includes unreconstructed remains.

The old and new bridges run nearly east–west, so sunrise and sunset are the best times to work with the light. Frame the historic trusses with the water and newer bridge in view; the water shifts from turquoise to deep blue. Rays, sea turtles, dolphins, fish, and coastal birds are possible sights below, but wildlife is never guaranteed.