The 36th Infantry Division was originally activated as the 15th Division, a Army National Guard Division from Texas and Oklahoma. The designation was changed to the 36th Division in 1917, possibly in July. It consisted of the 71st Infantry Brigade (141st and 142nd Infantry Regiments) and the 72nd Infantry Brigade (143rd and 144th Infantry Regiments). The unit was sent to Europe in July 1918 and conducted major operations in the Meuse-Argonne Offensive. During World War I, the division suffered 2,584 casualties consisting of 466 killed in action, and 2,118 wounded in action. The unit was inactivated in June 1919.