With Lee defeated at Gettysburg, the Union Army pursued him as he retreated back into Virginia. In September, the 1st Division was reorganized and the 140th was now assigned to the 1st Brigade, under the command of Col. Nelson Miles. For the remainder of 1863, the regiment was involved in a series of advances and retrograde movements in Northern Virginia with the II Corps, including limited involvement at the Battle of Bristoe Station on October 14, before finally settling into winter encampment.