Pre-World War I
* 18th Division: A National Guard division established in early 1917 consisting of Arkansas, Louisiana, and Mississippi. By the end of that same year, the 18th Division became the 39th Division (later the 39th Infantry Division).World War I
* 18th Division (World War I): Organized in 1918 as a regular army and national army division for World War I, the 18th Division did not go overseas and demobilized in February 1919 at Camp Travis, Texas. Either of these two divisions would have included the 35th Infantry Brigade and the 36th Infantry Brigade.Order of battle
Division commander: Colonel James H. Frier (interim), August 21, 1918-September 15, 1918; Brigadier General George H. Estes, September 16, 1918-October 14, 1918; Colonel James H. Frier (interim), October 14, 1918-October 23, 1918; Brigadier GeneralWorld War II
* 18th Armored Division: Placed on rolls for World War II, the 18th Armored Division was never organized. * 18th Airborne Division: a "phantom" division in World War II.References
United States Army divisions of World War I Military units and formations established in 1917 Military units and formations disestablished in 1919 {{US-Army-stub