Despite the results of the 15th, Hood determined to fight. That night he pulled his army back two miles to a more compact line, anchored on both flanks by hills along the Franklin Pike (US 31 today) and Granny White Pike. He also reorganized, placing A.P. Stewart’s battered corps in the center and moving B.F. Cheatham’s corps from right to left. S.D. Lee’s corps took over the right flank. His men spent the night maneuvering and entrenching, and were tired at daybreak.
Thomas had rested his army in place over the night, and awaited Hood’s next move. Finding the Confederates had retreated, Thomas probed forward and spent the morning of December 16 reconnoitering the Confederate positions and deploying for an attack. He determined to follow the same plan from the previous day: feint against the Confederate right, while crushing Hood’s left.
The diversion started at 3 P.M. as Steedman’s division, plus elements of Wood’s IV Corps, attacked astride the Franklin Pike. This time Hood was enticed to send reinforcements from Cheatham’s corps, weakening his left.
Meanwhile Wilson’s cavalry nipped at the Confederate left rear, forcing Cheatham to further stretch his razor-thin line. Thomas directed Schofield to attack the Confederate fortifications overlooking the Granny White Pike (on an eminence soon to be known as Shy’s Hill). Schofield demurred, citing the strength of the Confederate fortifications and unknown numbers of defenders.
Schofield may not have seen it, but one man did: Brigadier General John McArthur, commanding a division in Smith’s corps. Looking at Shy’s Hill, McArthur’s Federals noticed that the Confederate fortifications there were poorly placed and not fully constructed. At 3:30, McArthur sent a message to his superiors that he would attack in five minutes unless otherwise directed. No orders came, and McArthur’s division attacked Shy’s Hill and the area around it. Quickly swarming and overrunning the defenses, McArthur’s men cracked Cheatham’s line. Neighboring Federal units swung into action, and Cheatham’s corps collapsed. This precipitated a general Confederate retreat, which swept Hood’s army off the field.
George Thomas had won one of the most complete victories for the United States in the Civil War, indeed in its history. In two days, he lost 3,061 casualties; Hood’s losses are unknown, but at least 4,000 Confederate prisoners were taken. Middle Tennessee was forever secured to the Union. Most importantly, the Confederacy’s second-largest army was irreversibly wrecked.