Traveling US 1 in the Keys

Mile Marker

As you trek into the Keys on our only highway, US 1, also known locally as the Overseas Highway, you should take note of the small green mile marker signs posted every mile starting just south of Florida City.

These signs give you mile marker information along the highway all the way to Key West, a distance of 125 miles.

Most Florida Keys locations will be identified by mile marker and whether they lie oceanside or bayside.

Florida Scenic Highway US1 aka Overseas Hwy

As you head south on the Overseas Highway going from Miami toward Key West oceanside will be on your left and bayside on you right. Keep this in mind as you travel our main highway. It will help you find things.

Here on the Fabulous Florida Keys site we'll identify locations along the Overseas Highway with the MM abbreviation followed by a number for mile marker location.

Mile marker numbers start at 126 just south of Florida City, as you cross the new Jewfish Creek Bride and land on Key Largo you'll be at mile marker 106.

The numbers will keep getting smaller as you head south and west toward Key West where you'll eventually reach mile marker 0.

Here's a list of approximate MM numbers identifying cities, towns, and areas of the Keys.

• The Florida Stretch - MM 126 to MM 106
• Key Largo - MM 106 to MM 94
• Tavernier - MM 94 to MM 90.5
• Islamorada - MM 90.5 to MM 73
• Marathon - MM 60 to MM 47
• Key West - MM 5 to MM 0

The Overseas highway can be a tricky road to travel for the uninitiated. Here are a few helpful tips.

You’ll need to closely heed any school zone signs you find here. Some of the zones are unusually long and have speed limits as slow as 20 mph. When the flashing light at the beginning of the zone is on you must reduce to the posted speed.

Police regularly use unmarked cars to monitor Florida Keys traffic

Local police monitor active school zones closely and show no mercy to speeders of traffic violators. I can tell you every time I traverse the school zone at MM 105 in front of the Key Largo School I see someone being ticketed.

Police regularly setup DUI stops on US 1 in the Keys. These zones are announced in the local newspapers weekly in local newspapers. Bottom line, don’t drink and drive here.

In the lower Keys you’ll find a reduced speed zone on Big Pine Key marked with large signs and flashing lights to protect the Key deer.

Over its full length in the Florida Keys US 1 will be either a 2-lane road, 4-lane road, or 4-lane divided highway. In the areas where it is a 4-lane divided highway extreme caution must be used when entering or leaving the roadway to make sure you’re not trying to travel the wrong way down the highway. It is very easy to make this mistake if you’re unfamiliar.

In some parts of the Keys, State Road 905 known locally as the Old Road, parallels US 1 and offers an alternative route if traffic gets heavy or slows to a crawl. The speed limit on the Old Road is always lower than it is on the parallel section of US 1. The Old Road does not cross any Keys bridges so you’ll need to get back on the main highway prior to the next bridge.