The 91st Infantry Division (famously nicknamed as the "Wild West Division" with a "Fir Tree" as its Division insignia to symbolize its traditional home of the Far West) is an infantry division of the United States Army that fought in World War I and World War II. From 1946 until 2008, it was part of the United States Army Reserve. It was briefly inactivated from 2008 until 2010 when it was elevated back to a division size element as the 91st Training Division (Operations). History World War I Constituted on 5 August 1917 at Camp Lewis, Washington, near Tacoma, the division, commanded by Major General Henry Alexander Greene, soon thereafter departed for England in the summer of 1918. In September 1918, the division's first operation was in the St. Mihiel Offensive in France. Serving under the U.S. Army's V Corps, the division, now commanded by Major General William Johnston Jr., fought in the Meuse-Argonne Offensive and successfully helped to destroy the German First Guard Division and continued to smash through three successive enemy lines. Twelve days before the end of World War I, the division, as part of the VII Corps of the French Sixth Army, helped drive the Germans east across the Escaut River in the Battle of the Lys and the Escaut. The division was awarded separate campaign streamers for its active role in the Lorraine, Meuse-Argonne and Ypres-Lys campaigns. In 1919, the 91st was inactivated at the Presidio of San Francisco. The Division was composed of the following units: Headquarters, 91st Division 181st Infantry Brigade 361st Infantry Regiment 362nd Infantry Regiment 347th Machine Gun Battalion 182nd Infantry Brigade 363rd Infantry Regiment 364th Infantry Regiment 348th Machine Gun Battalion 166th Field Artillery Brigade 346th Field Artillery Regiment (75 mm) 347th Field Artillery Regiment (4.7") 348th Field Artillery Regiment (155 mm) 316th Trench Mortar Battery 346th Machine Gun Battalion 316th Engineer Regiment 316th Medical Regiment 316th Field Signal Battalion Headquarters Troop, 91st Division 316th Train Headquarters and Military Police 316th Ammunition Train 316th Supply Train 316th Engineer Train 316th Sanitary Train 361st, 36nd, 363rd, and 364th Ambulance Companies and Field Hospitals Interwar period After being reconstituted in 1921 as part of the Organized Reserves and being assigned to the state of California, the division then served as an administrative control center for the next 21 years. World War II As the early battles of World War II involving the