9813535 is a ZIP code in Marathon, Florida. It is located on the Florida Keys, in Monroe County, about halfway between Key Largo and Key West. The area is home to a variety of restaurants, resorts, activities and attractions. The Sombrero Beach is a popular destination, as are the many local wildlife centers that offer fishing, hiking, sailing, camping and snorkeling opportunities. Other attractions include Crane Point Museum and Nature Center, Florida Keys Aquarium Encounters, and the Dolphin Research Center.