After the long march back through its attack sector, the Yankee Division spent the next two weeks in corps reserve, where it finally had time to rest and refit. On 11 August, it entrained to the Chatillon training area where it at last began to train for a “war of movement.” For the first time, one unit history could claim that “the methods of open warfare dominated all study and drill.” Units practiced communicating while moving and working with aircraft. During this two-week period of training, a number of poorly trained enlisted replacements arrived (practically the last ones the division received during the war), and they had to be integrated into units and brought up to standards. At the same time, the division had to yield twenty-three officers and seventy-two precious NCOs for duty as instructors back in the United States. Nevertheless, the division finally conducted a couple of full-division maneuvers. On 27 August, it began its move back to the front lines to take part in the St. Mihiel attack.

The St. Mihiel Attack, 12–13 September 1918

The Yankee Division ultimately played a more prominent role in the St. Mihiel attack than anyone expected. During its initial advance over difficult terrain, it outpaced one veteran French division and kept pace with another. It then finished the battle with an impressive night-time advance that closed the salient from further enemy escape. The division captured thousands of German troops, while its own losses were light.