Marathon, Florida is considered the heart of the Florida Keys because of its location in the middle of the Florida Keys island chain. The area of Marathon consists of many Keys or islands starting with Long Key, the Conch Keys, Duck Key, Grassy Key, Boot Key, Crawl Key and Pigeon Key. Marathon is separated from the Lower Florida Keys on the south end by the Seven Mile Bridge. This bridge is famous, has been seen in many movies and is host to the Seven Mile Bridge Run each year.