The 1st Infantry Division is a combined armsdivision of the United States Army, and is the oldest continuously serving in the Regular Army.It has seen continuous service since its organization in 1917 during World War I. TheFirst Expeditionary Division, was designated the 1st Infantry Division, and constituted on May 24,1917
in the regular Army. And was organized on June 8 1917,at Fort Jay,
on Governors Island in New York Harbor under the command of Brigadier GeneralWilliam L. Sibert, from Army units then in service on the Mexico - United States border and at various Army posts throughout the United States.