Fort Mansfield and similar forts stretching from Galveston to Maine can be traced back to a joint Army-Navy Board created in 1883 known as the Gun Foundry Board. Its report a year later warned of the defenseless condition of the USA's coasts and recommended a system of fortifications to protect harbors and coastal cities from invasion. In 1885 this Board was replaced by what has become known as the Endicott Board which in 1886 issued formal recommendations for a major coastal defense network. Fort Mansfield was one of numerous coastal artillery installations constructed to guard the eastern entrance to Long Island Sound as part of the coastal defense network for New York City. It was named in honor of Joseph K. Mansfield (1803–1862) who had served as Chief Engineer Of The Army during the M