Conch Key is an island and unincorporated community in Monroe County, Florida, United States. It is located in the middle Florida Keys. U.S. 1 (the Overseas Highway) crosses the key at approximately mile markers 62-63, between Long Key and Duck Key. It is part of the census-designated place of Duck Key.Little Conch Key, at approximate mile marker 62.2 is also known as Walker's Island.