Located on U.S. Highway 1, at approximately mile markers 34--36, between Bahia Honda Key and Big Pine Key.

Gerdes, in his "Reconnaissance of the Florida Reefs and all the Keys" (1849) states: "The three small islands next to the West from Bahia Honda Harbor are called Summerlands Islands or Kays." U.S. Coast & Geodetic Survey chart #168, "Florida Reefs Long Key to Newfound Harbor Keys" (1863) shows Summerland Key

Originally, there were three keys at this location. They were connected by fills at the time the Florida East Coast Railway Extension was built. The Keys were West Summerland Key (westernmost), Middle Summerland Key (center), and no name has yet been found for the easternmost key. West Summerland retains its name, but the other two are known simply as the Spanish Harbor Keys. Named for the anchorage located between this key and Big Pine Key.