Louis Gustave De Russy (1795 – December 17, 1864) was an engineer and career United States Army officer who served as Major-General in the Louisiana Militia during the American Civil War. He was the oldest West Point graduate to serve in the Confederacy in that war. He is the younger brother of René Edward De Russy, a U.S. brigadier general, who remained with the Union during the war. Both men had forts named after them. That named for Louis is Fort DeRussy, constructed near Marksville, Louisiana during the Civil War.