City: Key Biscayne   County: Miami-Dade   Year: 2017
Location: 1200 Crandon Boulevard

In 1807, President Thomas Jefferson signed legislation calling for a survey of the United States’ coastlines. Initially coordinated by the U.S. Navy, the survey was taken over by the newly-formed, civilian U.S. Coast Survey team in 1832. Led by superintendent Alexander Dallas Bache, a U.S. Coast Survey team erected two base markers, each weighing over 3.5 tons, on Key Biscayne in 1855. The team established a 3.6-mile baseline that was used in conjunction with other surveys to create some of the first truly accurate maps of the Florida coastline and reefs. The north marker is located on land that is now within the Crandon Park Golf Course. The original south marker was on land 300 feet south of the Cape Florida Lighthouse, but had disappeared into the sea by 1883 as the shoreline eroded. In 1988, local professional land surveyors located remnants of the southern marker in 12 feet of water and the U.S. Air Force 301st Aerospace Rescue and Recovery Squadron recovered it. The recovery effort helped to preserve some physical remains representing the Coast Survey team’s struggle to measure and map Florida’s coast.