Key Largo is a census-designated place located in the U.S. state of Florida. It is within Monroe County on the island of Key Largo in the upper Florida Keys. It has a total area of 15.3 square miles at 25°6′24″N 80°25′48″W. The elevation is 7 feet above sea level. As of the 2010 census data, it had a total population of 10,433. The population density was 776.9/sq mi. It has Zip code 33037.