The Union troops at Fort Mill Ridge continued their duties until June 14, 1863. Then, in response to Lee's invasion of Pennsylvania, Campbell's command was ordered to concentrate with the rest of their division at New Creek (Keyser). Confederate General Imboden's Northwestern Brigade had left the Shenandoah Valley on June 9th, occupied Romney on June 16th, and freely roamed through the countryside taking an unoccupied Cumberland on June 17th before moving east, destroying the railroad as they went.
With Lee's defeat at Gettysburg on July 3rd, the Union troops at New Creek were ordered to move eastward along the Potomac River toward Martinsburg. On August 15th, Campbell's command returned from the east and reoccupied the encampment at Fort Mill Ridge.
Throughout the remaining summer and fall, the Union troops resumed their duties of picketing, patrolling, and drilling. Military activities in West Virginia in the fall of 1863, however, were generally quiet. On November 6, 1863 Campbell's command was ordered north to Springfield. Their departure ended the Union occupation of Fort Mill Ridge and Romney for the remainder of the war. The region continued to be a contested area, however, with forces of both sides passing through the area on various raids and missions until the ending of hostilities.
Fri 12. we had grand revew today. we sent our knapsacks and all of our baggage to New Crick today. Sat 13. vary warm. I am on battery gard. it is a litening tonight. Sun 14. warm today. we got marching orders for New Crick. we left Romney in the eaving, marched till three at night, halted in a mile and 1/2 of New Crick.
Diary of Joshua Winters, June 1863.