Big Creek Gap was one of the few natural openings through the Cumberland Mountains in the region, and during the Civil War its narrow, steep corridor made travel hazardous even for lightly loaded wagons. About thirty miles southwest of Cumberland Gap, a main migration route and strategic gateway, it offered a way to flank Confederate defenses after military engineers fortified Cumberland Gap and regarded it as impregnable from the north and east. East Tennessee Unionists alerted Federal commanders to this possibility, and in March 1862 a detachment of Union soldiers, including a company of Campbell County men under Capt. Joseph A. Cooper, first pushed through Big Creek Gap and routed nearby Confederate cavalry. In June, a larger operation under U.S. Gen. George W. Morgan helped bring about a bloodless Confederate withdrawal from Cumberland Gap, though control of that pass later changed hands several times. Big Creek Gap itself was also defended: in the summer of 1861, the 19th Tennessee Infantry and other Confederate units watched the state border here and tried to prevent local men from joining the Union army in Kentucky, and remnants of earthworks, rifle pits, gun emplacements, and ammunition dumps used by both sides still survive as Campbell County's only known Civil War-era fortifications.