Isle Phelipeaux (or Île Philippaux) and Isle Pontchartrain are phantom islands in Lake Superior, believed at one time to be real, shown on early maps, such as the Mitchell Map, of Lake Superior as located between the Keweenaw Peninsula and Isle Royale. [1] Phantom islands are islands that are believed to exist and appear on maps for a period of time (sometimes centuries), and then are removed after they are proven not to exist (or the general population stops believing that they exist). ... Lake Superior, bounded by Ontario, Canada and Minnesota, USA, to the north and Wisconsin and Michigan, USA, to the south, is the largest of North Americas Great Lakes. ... The Mitchell Map Mitchell Map is the common name used to refer to a map made by John Mitchell and all the various reprints made during the late 18th century. ... Lake Superior, bounded by Ontario, Canada and Minnesota, USA, to the north and Wisconsin and Michigan, USA, to the south, is the largest of North Americas Great Lakes. ... The Keweenaw Peninsula is the most northern part of Michigans Upper Peninsula. ... Isle Royale is an island of the Great Lakes, located in the northwest of Lake Superior. ...

Although non-existent, Isle Phelipeaux was referenced in the 1783 Treaty of Paris that ended the American Revolutionary War. A portion of the boundary between the United States and British colonies in Canada was described as running "through Lake Superior northward of the Isles Royal and Phelipeaux to the Long Lake." It had first appeared on a map prepared by the cartographer Bellin in 1744.[2] It continued to appear on maps of Lake Superior for many years, including the Mitchell map used in the Paris peace talks, in 1783. [3] Painting by Benjamin West depicting (from left to right) John Jay, John Adams, Benjamin Franklin, Henry Laurens, and William Temple Franklin. ... This article is about military actions only. ...

During the 1820s, when surveys were attempting to determine the International Boundary from the Lake of the Woods to Lake Superior, it was also discovered that Isle Phelipeaux did not exist and were unable to determine what body of water was meant by the Long Lake referenced in the treaty. [4] Canada and the United States of America share the longest common border among any two countries that is not militarized or actively patrolled. ... Lake of the Woods from space, May 1998 Lake of the Woods. ...

A likely reason given for the appearance on maps of this island and the similarly phantom Isle Pontchartrain, was to curry favor with the French government minister, Louis Phélypeaux, marquis de La Vrilliere, comte de Pontchartrain, in order to gain funding for additional voyages of exploration. Louis Phélypeaux (1643–1727), marquis de Phélypeaux (1667), comte de Maurepas (1687), comte de Pontchartrain (1699), known as the chancellor de Pontchartrain, was a French politician. ...