4th Bn - 9th Infantry Regt

The 4th Battalion, 9th Infantry Regiment was first constituted on 3 March 1855 in the Regular Army as Company D, 9th Infantry, and organized on 17 March 1855 at Fort Monroe, Virginia. It was consolidated in June 1869 with Company D, 27th Infantry, with the consolidated unit designated as Company D, 9th Infantry. Company D, 27th Infantry had been first constituted on 3 May 1861 in the Regular Army as Company D, 2nd Battalion, 18th Infantry and organized in October 1861 at Camp Thomas, Ohio. The unit was redesignated on 21 September 1866 as Company D, 27th Infantry before being consolidated with Company D, 9th Infantry.