Key Largo → Key West Drive Guide

Non-negotiable: there’s no drive in America quite like this one. US-1 leaves the mainland and walks out onto the ocean, hopping 42 bridges across 113 miles all the way to Key West’s Mile Marker 0. Skip it and you’ve never seen a road do this.

Why the Overseas Highway earns the drive

The water is turquoise on your right and jade on your left, and for stretches you can’t see land in either direction — just two lanes of asphalt and the Atlantic. The masterpiece is the Seven Mile Bridge, actually 6.79 miles of open water, where Henry Flagler’s Overseas Railroad once ran. That railroad reached Key West in 1912; the Category 5 Labor Day Hurricane of 1935 — 185-mph winds, an 18-foot storm surge — tore out more than 40 miles of track. Florida bought the wreckage and converted it to a highway that reopened in 1938. You’re driving on the bones of one of the boldest engineering failures in American history, and the old span still runs alongside the new one for much of the route.

The move

Take two days, not one. Leave Miami by mid-morning so you cross the Seven Mile Bridge before the afternoon sun turns the water into glare. Stop at Bahia Honda State Park to swim and walk out on the old bridge span — it’s the postcard angle on the new bridge, and the beach is the best in the chain. Overnight in the Middle Keys around Marathon so the second day is a relaxed run to Mile Marker 0 rather than a slog.

The honest catch — what to skip

Don’t try to do it in a day. Nonstop it’s 3.5 hours each way, and rushing it means you pass every reason the drive exists. Skip the middle-of-the-day Seven Mile crossing if you can — the glare is brutal and the two-lane stretches back up behind slow RVs with no passing lanes. And August through October is a real gamble: this is the only road in and out, and hurricane evacuations shut it down with little warning.

Logistics

The highway itself is free — no tolls on US-1 through the Keys — so the cost is gas, a night’s room, and whatever you stop for. Mile markers count down from 106 in Key Largo to 0 in Key West, which is how locals give directions, so watch the little green numbers. Fuel up before the long open stretches; gas stations thin out between the Middle Keys and Key West.

Nearby

The route runs Key Largo (dive John Pennekamp Coral Reef State Park) → Islamorada → Bahia Honda → Key West at Mile Marker 0. Reward yourself at the bottom with the pie that’s actually yellow, then push 70 miles past the end of the road to Dry Tortugas National Park. It’s one of the signature drives in the Florida guide.