It now appears that 1st and 5th Army will lose their identifications. 1st Army will become something like training and readiness command and 5th Army will become the army component command for Northern Command. The new 1st Army under whatever name it takes, will have the training validation and mobilization responsibility for all reserve components in CONUS. Meanwhile 5th Army will take on the armys military support to civil authoritys role for Northern Command.
While the 3rd Armys headquarters went to war in Saudi Arabia in 1991, it was noted that this was a headquarters too many. A smaller corps headquarters would do. Other nations, particularly in Europe, have advocated doing away with the field army since the 1970s. Its an idea that would not go away, and just kept gaining momentum. So, without much fanfare, or notice, a major piece of military history is slowly passing from the scene.
The field army has existed for thousands of years. But its starting to disappear, replaced by a new creature that controls air and naval forces, along with the ground pounders that traditionally comprised a field army. The new type of headquarters is usually called a joint command, plus some bits of gibberish. This has been a gradual process, which gained speed after the Cold War ended, and the last of the huge, old fashioned land forces, the Red Army of the Soviet Union, disintegrated. And so now it has come to pass that the two remaining American Continental Armies will go away. During World War II the U.S. Army had lots of field armies ( 1st, 3rd, 5th, etc.) During the Cold War these evolved into two different beasts; the Continental US Armies (CONUSAs) and the Army Component Commands overseas (7th Army in Europe and 8th Army in Korea). The CONUSAs started out as 1st 3rd, 4, 5th, and 6th. The CONUSAs evolved over time to organizations responsible mainly for reserve units. After much change, reforms and other events, the CONUSA ended up being just 1st Army and 5th Army. 1st Army was responsible for training validation and mobilization of reserve component units east of the Mississippi and 5th Army had everything west of the Mississippi. All the rest of the CONUSAs went out of existence. The other numbered Armies (3rd, 7th and 8th) still exist as the Army component of CENTCOM, EUCOM and PACOM respectively. These armies are entirely different beast than the CONUSAs.