Embassy of the United States, London
There has been an American person to represent the United States in London since John Adams in 1785.  The ambassador's home has been Winfield House since 1955. The main embassy building is in Nine Elms, Battersea, London, by the River Thames and has been opened to everyone since 13 December 2017, and was officially opened in January 2018. Before the embassy moved into the current building, the main building was in Grosvenor Square, Westminster, London.