Louis Lebègue de Presle Duportail (French: [lwi ləbɛɡ dəpʁɛl dypɔʁtaj]; 14 May 1743 – 12 August 1802) was a French military leader who served as a volunteer and the chief engineer in the Continental Army during the American Revolutionary War. He also served as the French Minister of Defense during the beginning of the French Revolution.
Duportail was born near Orléans, France, in 1743. He graduated from the royal engineer school in Mézières, France, as a qualified engineer officer in 1765. Promoted to lieutenant colonel in the Royal Corps of Engineers, Duportail was secretly sent to America in March 1777 to serve in Washington's Continental Army under an agreement between Benjamin Franklin and the government of King Louis XVI of France. He was appointed colonel and commander of all engineers in the Continental Army, July 1777; brigadier general, November 17, 1777; commander, Corps of Engineers, May 1779; and major general (Brevet), November 16, 1781.
Duportail participated in fortifications planning from Boston, Massachusetts to Charleston, South Carolina and helped Washington evolve the primarily defensive military strategy that wore down the British Army. He also directed the construction of siege works at the Battle of Yorktown, site of the decisive Franco-American victory of the Revolutionary War. During the encampment at Valley Forge in late-1777 and early-1778, his headquarters was at Cressbrook Farm.