Historic Marker number three is located at 322 Duval Street between Caroline and Eaton Street. The oldest house in southern Florida was originally located a block or two away on Whitehead Street. The Oldest House has weathered hurricanes, fires and the harsh marine environment. Its resiliency is largely due to the skill of Captain Richard Cussans, a ship's carpenter who built the house. His mortise and tenon joinery, horizontal wallboards and ventilation hatches or "scuttles" have enabled the house to withstand the tests of time.The expansion of the city from its deep-water port beginnings was slowed by the existence of a natural salt-water pond that ran from Whitehead Street through the old city hall site to the port. By 1829 a large portion of the lake had been filled and the structure was moved to its current location.The house was enlarged to four rooms with a center hall to accommodate its next residents, Captain Francis Watlington, his wife Emeline and their nine daughters.Captain Watlington held a number of maritime positions in his career including pilot, port warden, wrecker, Coastal Pilot for the U.S. Navy during the Second Seminal War and the Inspector of Customs. One of his duties for the Customs Office was to oversee the "light ships," vessels that were used as floating lighthouses at dangerous coastal and reef locations.Captain Watlington served in the Florida House of Representatives from 1858 to 1861 only to resign his office at the outbreak of the Civil War. He joined the Confederate navy in Mobile Alabama and served as the captain of the gunboat Gaines of the Naval Squadron.With the Union victory in Mobile, Captain Watlington surrendered in May of 1865 and was paroled shortly after. He returned to Key West and his family and descendants lived in the house until the early 1970's.