There are certain places in the world that stop you in your tracks the first time you see them. Seven Mile Bridge in the Florida Keys is one of those places. Stretching nearly seven miles across the sparkling blue-green waters between Marathon and the Lower Keys, this engineering marvel isn’t just a road — it’s one of the most breathtaking drives in the United States and an absolute must-see for anyone visiting the Florida Keys.
Whether you’re driving across it for the first time with the windows down, walking the historic Old Bridge at sunrise, casting a line into the deep channel below, or simply watching the sun melt into the Gulf of Mexico from the bridge’s edge, Seven Mile Bridge delivers unforgettable moments every single day.
And the best part? When you stay at Blackfin Resort & Marina in Marathon, you’re just minutes from this iconic landmark. Here’s everything you need to know about Seven Mile Bridge — its history, how to explore it, and why it should be at the top of your Florida Keys bucket list.
A Brief History of Seven Mile Bridge
Henry Flagler’s Impossible Dream
The story of Seven Mile Bridge begins with one of the most ambitious construction projects in American history. In the early 1900s, railroad tycoon Henry Flagler set out to build the Overseas Railroad — an extension of the Florida East Coast Railway that would connect mainland Florida all the way to Key West. Most people called it “Flagler’s Folly” and believed it was impossible.
The original Seven Mile Bridge, known today as the Old Seven Mile Bridge, was the crown jewel of this project. Completed in 1912, it required hundreds of workers, massive concrete arches, and sheer determination to build across open ocean. The bridge crossed Moser Channel, one of the deepest natural channels in the Keys, where the Atlantic Ocean meets the Gulf of Mexico.
When the Overseas Railroad was completed in 1912 and Flagler rode the first train into Key West, he proved every doubter wrong. It was, and still is, one of the greatest engineering achievements of the 20th century.
From Railroad to Highway
The Labor Day Hurricane of 1935 — one of the most powerful hurricanes ever to hit the United States — devastated the Overseas Railroad and killed over 400 people. The railroad was never rebuilt, but the existing bridges and roadbed were converted into the Overseas Highway, which opened in 1938 and became part of U.S. Route 1.
For decades, travelers drove across the narrow, two-lane Old Seven Mile Bridge with nothing but open water on either side. It was thrilling, terrifying, and absolutely unforgettable.
The Modern Bridge
By the 1970s, the old bridge was showing its age, and a modern replacement was needed. The new Seven Mile Bridge opened in 1982 — a wider, higher, four-lane bridge that could handle modern traffic and withstand Category 5 hurricane winds. It sits alongside the old bridge, creating the iconic parallel-bridge view that has appeared in countless movies, TV shows, and photographs.
You may recognize it from films like True Lies, 2 Fast 2 Furious, and License to Kill — Hollywood loves this bridge as much as visitors do.
[Image: Side-by-side view of the Old and New Seven Mile Bridge. Alt text: “The historic Old Seven Mile Bridge alongside the modern bridge in Marathon Florida Keys”]
Walking & Biking the Old Seven Mile Bridge
After years of renovation, a 2.2-mile section of the Old Seven Mile Bridge reopened in 2022 as a pedestrian and cycling path — and it has quickly become one of the most popular things to do in Marathon. This beautifully restored section starts at the Marathon end (Mile Marker 47) and extends out to Pigeon Key, offering a walking and biking experience unlike anything else in Florida.
What to Expect
The path is flat, paved, and accessible, making it perfect for all ages and fitness levels. As you walk or ride out over the open water, you’ll be surrounded by panoramic views of the Atlantic Ocean to the east and the Gulf of Mexico to the west. The water below shifts between shades of turquoise, emerald, and deep sapphire depending on the time of day and the depth of the channel.
Keep your eyes peeled for wildlife along the way. It’s common to spot sea turtles surfacing for air, nurse sharks gliding through the shallows, dolphins playing in the current, pelicans diving for fish, and magnificent frigatebirds soaring overhead. During the spring tarpon migration (April through June), you can often see massive silver kings rolling at the surface near the bridge pilings.
Hours & Tips
- Hours: Open daily from sunrise to sunset (no nighttime access)
- Cost: Free for pedestrians and cyclists
- Parking: Free parking lot at the Marathon entrance near Mile Marker 47. Arrive early on weekends — it fills up fast
- Distance: 2 miles one way to Pigeon Key (4.4 miles round trip)
- Best time to go: Early morning for cooler temperatures and fewer crowds, or late afternoon for golden hour light and sunset views
- What to bring: Sunscreen, water, hat, sunglasses, and a camera. There is zero shade on the bridge
- Pro tip: Rent bikes from a local shop in Marathon for a faster trip, or walk at a leisurely pace and plan about 90 minutes to two hours for the full round trip
Insider tip from Blackfin Resort: Head out about 45 minutes before sunset. You’ll reach a perfect spot near the midpoint of the bridge just as the sky starts to turn, giving you front-row seats to one of the most spectacular sunsets in the Florida Keys. It’s an easy walk back in the twilight, and the views are absolutely stunning.
Pigeon Key: A Hidden Historic Island
At the end of the Old Bridge walkway sits Pigeon Key, a tiny five-acre island with a fascinating history. During the construction of Flagler’s railroad, Pigeon Key served as the main work camp for the hundreds of laborers who built Seven Mile Bridge. The island’s original early-1900s buildings have been beautifully preserved and now operate as a museum and marine science center.
When you arrive by foot or bike, you can explore the historic buildings, learn about the incredible engineering challenges of building the railroad across open ocean, and discover the island’s marine research programs. It’s a perfect complement to the bridge walk and gives the whole experience a deeper sense of history and meaning.
Pigeon Key also offers ferry service from Marathon for visitors who prefer not to walk the full distance. Check their website for current schedules, tour times, and admission fees.
[Image: Pigeon Key with the Old Bridge in background. Alt text: “Historic Pigeon Key island beneath the Old Seven Mile Bridge in the Florida Keys”]
Fishing at Seven Mile Bridge
Seven Mile Bridge isn’t just a beautiful landmark — it’s one of the best fishing spots in the entire Florida Keys. The bridge pilings create an underwater habitat that attracts an incredible variety of game fish, and the deep Moser Channel running beneath the bridge is a natural highway for migrating species.
Bridge Fishing from the Old Bridge
You can fish directly from the Old Seven Mile Bridge — it’s one of the longest fishing piers in the world. Anglers line up along the railing with their rods, casting into the channels and around the bridge pilings. No boat needed, no charter required — just grab your gear and walk out.
Common catches from the bridge include:
- Tarpon (April – June) — The bridge is legendary for tarpon fishing during the spring migration. Massive silver kings, often 80–150+ pounds, stack up in Moser Channel
- Yellowtail snapper — Year-round and excellent table fare
- Mangrove snapper — Abundant around the pilings, especially at night
- Permit — One of the most prized catches in the Keys, often spotted near the bridge
- Barracuda — Aggressive and exciting to catch
- Jack crevalle — Powerful fighters that put on a show
- Grouper — Found around deeper structure (check seasonal regulations)
- Sharks — Nurse sharks and blacktip sharks are commonly hooked near the bridge
Fishing by Boat Near the Bridge
For anglers with boat access, fishing around the Seven Mile Bridge pilings by water opens up even more opportunities. The deep channel beneath the bridge holds large tarpon, cobia, kingfish, and occasionally sailfish. The structure created by hundreds of concrete pilings provides habitat for snapper, grouper, and lobster.
If you’re staying at Blackfin Resort & Marina, you can book a charter or launch from the marina and be fishing at the bridge within minutes. Ask the marina staff for local tips on tides and bait — they know exactly when and where the fish are biting.
Fishing Tips & Regulations
- A valid Florida saltwater fishing license is required (available online at GoOutdoorsFlorida.com or at local tackle shops)
- Live shrimp, live pilchards, and cut bait are the most effective baits for bridge fishing
- Tarpon are catch-and-release only unless you purchase a special tarpon tag
- Check current FWC regulations for size limits, bag limits, and seasonal closures before you fish
- Early morning, late afternoon, and night fishing tend to produce the best results at the bridge
Related: For a comprehensive guide to all the best fishing spots in Marathon, check out our post on Top Fishing Spots Near Blackfin Resort in Marathon, FL.
Sunset Views: Why Seven Mile Bridge Is a Front-Row Seat
If there’s one thing the Florida Keys are famous for, it’s the sunsets — and there may be no better vantage point in the entire island chain than Seven Mile Bridge. Because the bridge stretches across open water with unobstructed views to the west, you get a panoramic sunset experience that’s hard to match anywhere else.
From the Old Bridge walkway, you can watch the sun drop below the horizon over the Gulf of Mexico with nothing but water, sky, and the silhouette of the old railroad pilings framing the scene. The colors are extraordinary — deep oranges, pinks, purples, and golds reflecting off the calm water in every direction.
It’s also a popular spot for photographers. The parallel lines of the Old and New bridges, the arches, and the vast open water create compositions you simply can’t get anywhere else.
Related: Discover more amazing sunset spots in our guide to The Best Sunset Spots in Marathon, Florida.
[Image: Sunset over Seven Mile Bridge with the Old Bridge silhouetted. Alt text: “Stunning sunset over Seven Mile Bridge in the Florida Keys from the Old Bridge walkway”]
Driving Across Seven Mile Bridge
Even if you never get out of your car, driving across Seven Mile Bridge is an experience in itself. As you travel along U.S. 1 between Marathon and the Lower Keys, the road stretches out ahead of you in a seemingly endless line across the open ocean. The water shimmers on both sides, and on a clear day you can see for miles in every direction.
The drive takes about 10 minutes at the posted speed limit. There’s no stopping or pulling over on the new bridge (it’s a highway), so the Old Bridge is where you’ll want to go for walking, fishing, and photos. But the drive itself — especially on a sunny day with the windows down — is pure Florida Keys magic.
Pro tip: If you’re driving to Key West from Marathon, time your trip so you cross Seven Mile Bridge in the late afternoon. The light is golden, the water glows, and you’ll understand why this is consistently ranked among the most scenic drives in America.
The Annual Seven Mile Bridge Run
Every April, the new Seven Mile Bridge is closed to traffic for one of the most unique running events in the world: the Seven Mile Bridge Run. Approximately 1,500 runners race across the bridge in a 6.79-mile dash over open ocean, with nothing but turquoise water below and blue sky above.
The race is so popular that entry is determined by lottery — demand far exceeds the limited spots available. If you’re a runner and you get the chance to participate, it’s a bucket-list experience. Even if you’re not running, it’s a fun event to watch and a great excuse to visit Marathon in the spring.
Related: Planning a spring trip? Read our guide on Florida Keys in Spring: Why March–May Is the Best Time to Visit.
10 Fun Facts About Seven Mile Bridge
- Despite its name, the bridge is actually 6.79 miles long — close enough to round up
- The original bridge used over 546 concrete arches to span the open water
- It was the longest bridge in the world when the original was completed in 1912
- The modern bridge was designed to withstand Category 5 hurricane-force winds
- The Old Bridge is listed on the National Register of Historic Places
- Moser Channel beneath the bridge reaches depths of over 60 feet
- The bridge has appeared in at least six major Hollywood films
- It connects Marathon (Mile Marker 47) to Little Duck Key (Mile Marker 40)
- The $45 million renovation of the Old Bridge took several years to complete
- The bridge is the dividing line between the Middle Keys and the Lower Keys
Planning Your Visit: What You Need to Know
Getting There
Seven Mile Bridge is located on U.S. Route 1 (the Overseas Highway) between Mile Marker 47 in Marathon and Mile Marker 40 in the Lower Keys. The entrance to the Old Bridge walking path is on the Marathon side near MM 47, right off U.S. 1. If you’re staying at Blackfin Resort & Marina, it’s just a short drive from the resort.
Best Time to Visit
Seven Mile Bridge is stunning year-round, but each season offers something different. Winter (December–February) brings cooler temperatures and lower humidity, making bridge walks more comfortable. Spring (March–May) is ideal for tarpon fishing and the annual bridge run. Summer offers the longest days and warmest water for spotting marine life. Fall is the quietest season with fewer crowds and beautiful light.
What to Do in a Day
Here’s a perfect Seven Mile Bridge day trip from Blackfin Resort:
- Morning: Walk or bike the Old Bridge to Pigeon Key. Explore the museum and enjoy the views
- Lunch: Head back to Marathon for a meal at the Hurricane Grille — it’s right at Blackfin Resort and serves excellent seafood with waterfront views
- Afternoon: Grab your fishing gear and spend a few hours casting from the Old Bridge, or book a charter from Blackfin Marina to fish the deep channel by boat
- Evening: Return to the Old Bridge for sunset. Bring a cold drink and watch the sky explode with color
Why Blackfin Resort Is Your Perfect Home Base
Blackfin Resort & Marina is ideally located in the heart of Marathon, just minutes from Seven Mile Bridge. After a morning walk on the Old Bridge or an afternoon of fishing, you can relax at the resort’s waterfront pool, grab fresh seafood at the Hurricane Grille, or plan your next adventure with the help of the marina team.
Whether you’re here for the fishing, the history, the sunsets, or simply the thrill of crossing one of the most famous bridges in America, Marathon and Blackfin Resort put you right where the action is.
Ready to experience Seven Mile Bridge for yourself? Book your stay at Blackfin Resort & Marina today and discover why Marathon is the heart of the Florida Keys.