Joseph-Francois Mangin (fl. c. 1750 - 1812) was an architect, city surveyor, and civil engineer active in New York during the late 18th and early 19th century. Mangin was born and educated in France where he apprenticed under Ange-Jacques Gabriel in the design of the Place de la Concorde, Paris. He moved to New York city in 1786 and was admitted as a Freeman of New York on May 9, 1796. He submitted several projects to the Common Council of New York, including a recommendation to drain the Collect Pond and various improvements to the port facilities. In 1799 he was commissioned to make a large scale plan of New York City. He presented the plan to the Common Council in 1801. The council was appalled by the plan, which reimagined New York City in an idealized from complete with non-existent streets and other improvements that never came to pass. Mangin even added streets such as Mangin Street and Goerck Street which would have been submerged under the East River had they actually existed. Mangin Street did eventually appear and still partially exists under the Williamsburg Bridge between Baruch Place and East Houston. South Street, another of Mangin's inventions, is far better known. Mangin designed this map in partnership with Casimir Goerck, a well-known New York Surveyor active in the late 18th century. Goreck died before the plan could be presented to the council and, to us it is highly doubtfully that he would have allowed such an inaccurate production to bear his distinguished name - setting the responsibility for the failed Mangin-Goerck plan, as it came to be known, squarely on Mangin's shoulders. Mangin also claimed at various point to have designed the New York City Hall while in the employ of the hall's true designer John McComb. McComb unilaterally denied Mangin's claims which are generally regarded as spurious. Despite his failed plan and dubious claims, Mangin was a favorite with the Common Council and was commissioned to work on the 1811 Comissioner's Plan of New York City, a truly meritorious work that laid out the permanent street grid for most of Manhanttan.