First Army formed up in preparation to advance in the Meuse-Argonne campaign. It consisted of over 600,000 men in I Corps, III Corps, and V Corps. III Corps took the Army's east flank, protecting it as the Army advanced to Montfaucon, then Cunel and Romagne-sous-Montfaucon. The offensive was slow and hampered by inexperience of many of the divisions under the Army's command, though III Corps was effective in protecting its sector. They advanced through September and October, taking a few weeks for rest after the formation of Second United States Army. On 1 November, the First Army went on a general offensive, pushing north to the Meuse River and the Barricourt Ridge. It was successful, pushing German forces back and advancing to the river until the end of the war. Around that time, III Corps received its shoulder sleeve insignia, approved it by telegram, though the insignia would not be officially authorized until 1922.