18th Infantry Regiment
Modern Era, United States, Infantry
The 18th Infantry Regiment was constituted in May 1861 during the Civil War enlargement of the Regular Army and fought in the western theater under George H. Thomas and other Union commanders. After the war it moved into the Indian campaigns and later to overseas service in the Spanish-American War and the Philippine-American War. Like the 16th Infantry, it would eventually become one of the long-associated regiments of the 1st Infantry Division.
In the twentieth century that 1st Division identity became central. The regiment served with the 1st Infantry Division in World War I and then again in World War II, when it fought through North Africa, Sicily, Normandy, northern France, the Rhineland, the Ardennes, and into Germany. This repeated association with the 1st Division made the 18th Infantry one of the Army's best-known divisional regimental lineages.
Vietnam continued that pattern at battalion level. The 1st and 2d Battalions, 18th Infantry served with the 1st Infantry Division in South Vietnam, adding another major combat chapter to the regiment's history. Later battalions also served in Berlin, at Fort Benning, and in operations from Desert Storm to Iraq, but the clearest twentieth-century through-line remained the regiment's repeated service under the 1st Infantry Division in the world wars and Vietnam.
The 18th Infantry Regiment therefore stands as another example of an old Civil War-born Regular Army regiment whose identity became deeply tied to a single division. Its lineage links Chattanooga and Atlanta to Normandy, Vietnam, and the modern expeditionary Army.
Battalion Page
A dedicated battalion subpage now collects the regiment's known battalion icons and short sketches for the 1st, 2d, and 3d Battalions. Open the 18th Infantry Regiment Battalions page.