The U.S. 82nd Airborne Division, commanded by Major General Matthew Ridgway, was a veteran outfit, with two of its units, the 504th and 505th Parachute Infantry Regiments (PIR), making combat jumps into Sicily and Italy. However, the 504th had not arrived in England in time to train for Operation Neptune, and had been replaced in the mission by the unblooded 507th and 508th PIRs, both temporarily attached for the operation (the 507th later transferring to the 17th Airborne Division). Because of its previous combat experience, the 82nd Airborne Division was assigned the riskier of the two jump missions, into the center of the Cotentin. Its final regiment, the 325th Glider Infantry Regiment, was scheduled to fly in on June 7.