The Seven Mile Bridge is a famous bridge in the Florida Keys, in Monroe County, Florida, United States. It connects Knight’s Key (part of the city of Marathon, Florida) in the Middle Keys to Little Duck Key in the Lower Keys. Among the longest bridges in existence when it was built, it is one of the many bridges on US 1 in the Keys, where the road is called the Overseas Highway.
There are two bridges in this location. The older bridge, originally known as the Knights Key-Pigeon Key-Moser Channel-Pacet Channel Bridge, was constructed from 1909-1912 under the direction of Henry Flagler as part of the Florida East Coast Railway’s Key West Extension, also known as the Overseas Railroad.