Butts Hill Fort (or Windmill Hill) evolved along the way. The British called this area Windmill Hill because it was a traditional site for a windmill. The Americans called this area “Butts Hill” after the John Butts family that held the land when the war began. The outlines you see at the Fort date from the improvements made by the Americans and French masons from 1780 to 1781. It is at this point that the fortifications at Butts Hill became Butts Hill Fort.
Resources:
Bartlett, John R., editor: Records of the Colony of Rhode Island and Providence Plantations, in New England (Volume IX) 1780 to 1783.
Diary of Frederick Mackenzie: Giving a Daily Narrative of His Military Service as an Officer of the Regiment of Royal Welch Fusiliers during the Years 1775-1781 in Massachusetts, Rhode Island, and New York, Volume I & II
Revolutionary War Plans in collection of the William Clements Library: University of Michigan.
Diagram from Planning, Preservation and Management Plan for Butts Hill Fort, Portsmouth, RI. A Project of the Rhode Island Marine Archaeology Project.
Map: http://library.providence.edu/encompass/rhode-island-in-the-american-revolution/primary-sources/map-of-the-siege-of-newport/
Plan de Rhodes-Island, et position de l’armée françoise a Newport. [1780] Map. https://www.loc.gov/item/gm71002156/.
Stone,Edwin, Our French Allies. Providence Press Company, 1884. P. xvi
Sullivan’s letter to the Continental Congress which was published in the Providence Gazette, September 26, 1778.