Outdoor Sports keys intermediate

Florida Keys Overseas Heritage Trail — 106 Miles of Ocean-to-Ocean Riding

A 106-mile paved trail from Key Largo to Key West, built on Henry Flagler's 1912 Overseas Railroad. Twenty-three preserved historic bridges, including the restored 2.2-mile Old Seven Mile. The only US bike route that crosses to a tropical island.

by Silvio Alves May 15, 2026

Cyclist on the old Seven Mile Bridge with turquoise water below in the Florida Keys

Old Seven Mile Bridge, Marathon — January — Wikimedia Commons · Seven-mile Historic Bridge, Florida Keys · CC BY-SA 4.0

You roll onto the Old Seven Mile Bridge at sunrise and the first thing you notice is the silence. US-1 is humming a mile north on the new span — trucks, RVs, the commute to Key West — and you are on 2.2 miles of restored 1912 concrete with no cars on it. Just pelicans, the wake of a skiff below, and turquoise water that makes you stop pedalling.

The Florida Keys Overseas Heritage Trail is the only paved bike trail in the United States that crosses open ocean to a tropical island. 106 miles, Key Largo to Key West, on top of one of the strangest pieces of American engineering history.

What it is

A 106-mile multi-use paved trail managed by Florida State Parks, from MM 106 in Key Largo south to MM 0 in Key West. About 91 miles (~87%) are complete and signed as of 2024; FL DOT is closing the remaining 15 miles of street-section gaps.

The route sits on the rights-of-way of Henry Flagler’s Overseas Railroad, completed 1912 and destroyed by the 1935 Labor Day Hurricane — still one of the most violent storms ever to strike the United States. Twenty-three of Flagler’s original bridges were preserved as the trail’s defining feature: the Old Seven Mile Bridge (reopened 2022 after an $80M restoration), the Bahia Honda Bridge, the Long Key Viaduct. You are not riding next to history — you are riding on it.

Most of the trail parallels US-1, separated by a traffic barrier or vegetated buffer. A few segments still drop you onto signed bike lanes through Marathon and Key West — which is why purists call it “mostly” off-road.

What you do

You section-ride it, or you thru-ride it.

The classic thru-ride is Key Largo to Key West in 4 to 5 days, averaging 20–25 miles a day. North-to-south is the only sane direction: prevailing easterlies put a quartering tailwind on your back the whole way, and the finish is rolling into Mallory Square at sunset.

Day-rides work just as well. Best starter: Key Largo MM 106 → Tavernier, 18 miles through Lake Surprise. Best single day: Marathon to Bahia Honda, crossing the Old Seven Mile then climbing the Old Bahia Honda ramp for the postcard shot.

Outfitters: Big Pine Bicycle Center (MM 31), Marathon Bike Shop (MM 50), Key West Bike Shop. Rentals $25–40/day, return shuttle $50–100 one-way. Overnight stops: Bahia Honda SP camping (book 11 months ahead), Long Key SP, Curry Hammock SP, plus motels in Tavernier, Marathon, and Big Pine.

Conditions, honestly

Best window: November through April. Trade winds lightest, humidity tolerable, afternoon thunderstorms haven’t started, hurricane season over. June through September is hot, wet, lightning-prone, and inside the Atlantic hurricane window — not when you want to be 70 miles into a bridge ride.

Wind direction matters more here than on any other Florida trail. Prevailing easterlies blow 10–18 mph most days. North-to-south puts the wind on your back quarter. South-to-north on a 20-knot day is brutal.

Sun exposure is the other thing nobody warns you about. No canopy on the bridges — long sleeves, a cap under the helmet, and reef-safe sunscreen are not optional.

Irma (2017) wiped out long sections; rebuilding is mostly done but expect occasional reroutes. Cell is solid 4G/5G the whole route.

What it’s not

It is not 100% off-road. Street sections through parts of Marathon, Big Pine, and Key West still share a lane with cars. It is not a sea-to-sea greenway, not yet. And it is not technical — no climbs, no singletrack.

What it IS

It is the only bike trail in the United States that crosses 23 historic bridges to a tropical island. It gives you wildlife you don’t see anywhere else — Key deer on Big Pine, brown pelican on every bridge, manatee in marina canals, lemon shark under the Bahia Honda span — and ends at the southernmost point of the contiguous US.

It is also living archaeology. Every time you cross one of Flagler’s old bridges you are riding a structure that survived the storm that ended an industrial dream. The trains never came back, the highway took the route, and the railroad’s bones are now the prettiest bike infrastructure in the country.

Do it once north-to-south, with a tailwind. Walk the last hundred yards to the Southernmost Point buoy.