The four regiments raised by Sickles that comprised the first Excelsior Brigade were the 70th, 72nd, 73rd, and 74th New York Infantry. In October 1861, the 71st New York, along with the 70th through the 74th Regiments and 10 Companies of the 3rd Indiana Cavalry, formed the Second Excelsior Brigade under General Sickles. The brigade was placed under the overall divisional command of Maj. Gen. Joseph Hooker in October. Its initial tasks included assisting in the building of defenses around Washington and stopping resupply of the Confederates from Southern Maryland.