The First Army Division West is a division of the First United States Army. With its new role, the First Army developed two subordinate multi-component headquarters – one division to support the western United States and the other to support the eastern United States. First Army Division East was activated at Fort Meade, Maryland. First Army Division West was activated on 7 March 2007, at Fort Carson, Colorado, and was transferred to its current headquarters at Fort Hood, Texas as part of the 4th Infantry Division realignment. First Army Division West was established by the Department of the Army to provide training and readiness oversight and mobilization operations for an area of responsibility spanning the states and territories west of the Mississippi River. Division West partners with USAR and ARNG Leadership, during Pre, Post and De- Mobilization, to advise, assist and train Army formations, Individual Non-unit Replacements, and Department of the Army Civilians in a multi-component, integrated training environment to achieve Department of the Army directed readiness objectives enabling FORSCOM to provide Combatant Commanders trained and ready forces in support of worldwide requirements. Subordinate Commands The division is organized into five brigades located throughout the western United States with 37 total battalions. The 85th Division provides trained Observer/Controllers to assist during collective training exercises and mobilizations. 5th Armored Brigade – Fort Bliss, Texas. Formerly the 91st Division's 2nd Brigade. 120th Infantry Brigade – Fort Hood, Texas. Formerly the 75th Division's 2nd Brigade. 166th Aviation Brigade - Fort Hood, Texas 181st "Eagle" Infantry Brigade – Fort McCoy, Wisconsin. Formerly the 85th Division's 2nd Brigade. 189th "Bayonet" Infantry Brigade – Joint Base Lewis-McChord, Washington. Formerly the 78th Division's 4th Brigade. 85th "Custer" Army Reserve Support Command (West) - Arlington Heights, Illinois. Formerly the 85th Division External links https://www.first.army.mil/Mission/Units/Division-West/ References United States First Army Division West Headquarters, Public Affairs Office Divisions of the United States Army Military units and formations established in 2007