Summerland Key is an unincorporated community in Monroe County, Florida, United States. It is located in the lower Florida Keys on the island of Summerland Key. Summerland Key is a bedroom community located almost mid-way between the "large" cities of Marathon and Key West. It is home to the Brinton Environmental Center of the Florida National High Adventure Sea Base. Also located on Summerland Key is a field station for Mote Marine Laboratory. A private, 2550-foot community airstrip (FD51) is located just south of the Overseas Highway on West Shore Drive at mile marker 25 - Lat: N 2439.5 Long: W 08126.5 Elev: 4 .