Mile Marker 24 to 25.5 — Summerland Key is midway between the cities of Marathon and Key West. The island contains mostly single-family residential properties, with several commercial properties arrayed along U.S. 1. It is home to the Florida National High Adventure Sea Base’s Brinton Environmental Center and a field station for the Sarasota-based Mote Marine Laboratory. There is a private 2,550-foot-long community airstrip located just south of U.S. 1 on West Shore Drive (mile marker 25). Commercial ventures on U.S. 1 include restaurants, two gas stations, a hardware store, a marina and a small, locally owned grocery store. The majority of the island’s development is on its south side (oceanside), where there is a mix of canalfront, oceanfront and dry lot homes.