The engagement at Mossy Creek resulted from a Federal advance of over six thousand soldiers from Strawberry Plains on December 18, 1863, to pressure the Confederate army of Lieut. Gen. James Longstreet following its repulse at Knoxville. On December 22, the Southern army settled into winter quarters around Russellville, about thirty miles from Strawberry Plains. Longstreet’s cavalry, commanded by William Martin, patrolled a twenty-five-mile arc running from Rutledge to Dandridge centered on Mossy Creek (today’s Jefferson City). Martin kept Longstreet apprised of any Federal movements that might threaten the main Confederate army.
Brigadier General Samuel Sturgis and his Federal army arrived in New Market on December 23, and the next day he ordered two brigades of cavalry and an artillery battery to move to Dandridge and flank Confederate forces to the south of his main position. At the same time, he ordered an infantry division forward to Mossy Creek, leaving one infantry division behind in New Market as a reserve. The southern prong of the offensive met a Confederate brigade, commanded by Col. A. A. Russell, near Hay’s Ferry. During the ensuing engagement, the Federal brigades of Archibald Campbell and Israel Garrard received orders to retreat back to New Market. Garrard’s men rode out without serious opposition, while Campbell’s Brigade was almost encircled and captured. Campbell extricated the brigade with difficulty, but both he and Garrard successfully returned to New Market as directed.
On December 29, General Sturgis again divided his force and sent Colonel LaGrange down toward Dandridge to engage remaining rebel forces there. At 11 a.m., General Martin attacked the Federal line east of Mossy Creek with over two thousand men and two batteries of artillery. The Confederate army began to bend back the flanks of the Union position while the center, anchored by Captain Eli Lilly’s artillery battery, held back the rebel onslaught. At about 2 p.m., Lilly’s battery, low on ammunition and receiving accurate musket fire, retired to another hill behind A. P. Campbell’s brigade. At this point, a Southern victory seemed assured. As the Confederates under Brig. Gen. Frank Armstrong attempted to roll up the Federal line from north to south, Campbell ordered one of his cavalry regiments to attack Armstrong’s men. The Federals charged headlong into the southern line, wreaking havoc and stopping the Confederate advance. Over on the Union right, Colonel LaGrange’s men entered the fight after a hasty summons had brought them back from Dandridge. The cavalry charge and arrival of Federal reinforcements convinced General Martin that the time for retreat had come, and he made an orderly withdrawal to his position held before the start of battle. His army was also low on ammunition. During the evening, the Confederate army fell back to Morristown.
The Federals held their position at Mossy Creek, having inflicted possibly four hundred casualties on the Confederate side compared to over a hundred of their own. Sturgis’s army remained at Mossy Creek until active operations resumed at Dandridge during the middle of January.