Thomas Weir (American soldier) Thomas Weir (American soldier) Captain Thomas Benton Weir (b. September 28, 1838 -– d. December 9, 1876) was an officer in the 7th Cavalry Regiment (United States), notable for his participation in the Battle of the Little Bighorn, also known as Custer's Last Stand. Weir served under General George Armstrong Custer during the American Civil War, and after the war continued serving with Custer up to the famous battle in 1876. During the Little Bighorn Battle, Weir disobeyed orders to remain in a defensive position at Reno Hill and led a cavalry group that attempted to come to Custer's aid.
5th Cavalry Regiment Henry Thomas. The regiment was rebuilt with new officers and recruits loyal to the Union and was assigned to the Army of the Potomac under the command of General George McClellan. On 21 July 1861, the regiment participated in its first battle of the American Civil War, the First Battle of Bull Run; it was the last action in which they would be called the "2nd Cavalry." In the summer of 1861, all regular mounted regiments were re-designated as "cavalry", and being last in seniority among the existing regiments, the regiment was re-designated as the 5th United States Cavalry. During