The Overseas Highway is a 113-mile (181.9 km)highway carrying U.S. Route 1 (US 1) through the Florida Keys. Large parts of it were built on the former right-of-way of the Overseas Railroad, the Key West Extension of the Florida East Coast Railway.<br/> Since the 1950s the Overseas Highway has been refurbished into a main coastal highway between the cities of Miami and Key West, offering travelers an exotic roadway through a tropical savanna environment and access to the largest area of coral reefs on the USA mainland.