Major General Ambrose Burnside, commander of the Department and Army of the Ohio, began to advance against Knoxville, Tennessee. Burnside left Cincinnati, Ohio in mid-August 1863. The direct route ran through the Confederate-held Cumberland Gap. Burnside had been delayed in earlier attempts to move out against Knoxville and thus chose not to spend the time to force a passage of the gap. Instead he detached one brigade under Colonel John F. DeCourcy to pose a threat to Brigadier General John W. Frazer's 2,300 man garrison, while the rest of the army bypassed to the south over 40 miles in rugged mountainous terrain. DeCourcy had previously led a brigade in the 1862 operations against the Cumberland Gap under George W. Morgan.