FSX/P3D – Harsens Island Scenery (Z92, Michigan (MI), USA. The island was named for its first white settler, James (or Jacob) Harsen, a Dutchman, who came from New York state in about 1779 with his son-in-law Isaac Graveraet (or Graveret). Harsen bought the island from the Indians in 1783. It was also known as “Jacob Island” (also James or Jacobus Island) as late as 1809. The name of the post office, Sans Souci, was changed to “Harsens Island” in 1960. The nation “owning” the island was a disputed matter for many years. The 1783 Treaty of Paris that ended the American Revolutionary War described the international boundary line with imprecise terms in several places. By Fernando Angel Gonzalez.